path: root/gui-apps/wcm/files/wcm-0.11.0-r21-async-ipc.patch

diff --git a/src/backgrounds.cpp b/src/backgrounds.cpp
index b835825..1a18134 100644
--- a/src/backgrounds.cpp
+++ b/src/backgrounds.cpp
@@ -7,15 +7,43 @@ namespace
 using json = nlohmann::json;
 json empty_slot() { return {{"image", ""}, {"sizing", "fill"}, {"color", {0,0,0,0}}, {"opacity", 1.0}}; }
 json empty_layout() { return {{"mode", "transparent"}, {"image", empty_slot()}, {"monitors", json::object()}}; }
+void validate_background_snapshot(const json& data)
+{
+    data.at("revision").get<std::string>(); data.at("topology").get<std::string>();
+    data.at("error_message").get<std::string>(); data.at("applied").get<bool>();
+    auto slot = [] (const json& s)
+    {
+        s.at("image").get<std::string>(); s.at("sizing").get<std::string>(); s.at("opacity").get<double>();
+        if (!s.at("color").is_array() || s.at("color").size() != 4) throw std::runtime_error("Invalid background color");
+        for (auto& channel : s.at("color")) channel.get<double>();
+    };
+    auto layout = [&] (const json& l)
+    {
+        l.at("mode").get<std::string>(); slot(l.at("image"));
+        if (!l.at("monitors").is_object()) throw std::runtime_error("Invalid background monitors");
+        for (auto& image : l.at("monitors")) slot(image);
+    };
+    auto& profiles = data.at("settings").at("profiles");
+    if (!profiles.is_object() || !data.at("outputs").is_array()) throw std::runtime_error("Invalid background profiles");
+    for (auto& profile : profiles)
+    {
+        layout(profile.at("default"));
+        if (!profile.at("workspaces").is_object()) throw std::runtime_error("Invalid background workspaces");
+        for (auto& workspace : profile.at("workspaces")) layout(workspace);
+    }
+    for (auto& output : data.at("outputs"))
+    {
+        output.at("name").get<std::string>(); output.at("profile").get<std::string>();
+        if (!output.at("grid").is_array() || output.at("grid").size() != 2 || !output.at("monitors").is_array())
+            throw std::runtime_error("Invalid workspace output");
+        for (auto& dimension : output.at("grid")) dimension.get<int>();
+        for (auto& monitor : output.at("monitors")) monitor.at("name").get<std::string>();
+    }
+}
 void clear(Gtk::Box& box) { for (auto child : box.get_children()) box.remove(*child); }
 void label_style(Gtk::Label& label)
 { label.set_halign(Gtk::ALIGN_START); label.set_line_wrap(); label.set_max_width_chars(75); label.set_selectable(true); }
 }
-BackgroundsPage::json BackgroundsPage::request(const std::string& method, const json& data)
-{
-    wf::json_t input; wf::json_t::parse_string(data.dump(), input);
-    return json::parse(wcm_ipc_request(method, input).serialize());
-}
 BackgroundsPage::BackgroundsPage(const std::string& config) : Gtk::Box(Gtk::ORIENTATION_VERTICAL, 10), config_file(config)
 {
     set_border_width(12); pack_start(tabs, true, true);
@@ -45,11 +73,11 @@ BackgroundsPage::BackgroundsPage(const std::string& config) : Gtk::Box(Gtk::ORIE
             if (selected_workspace == "default") { show_layout(); return; }
             auto profile = state["outputs"][outputs.get_active_row_number()]["profile"].get<std::string>();
             if (draft["profiles"].contains(profile)) draft["profiles"][profile]["workspaces"].erase(selected_workspace);
-            changed();
+            ++edit_serial; changed(); status.set_text("Unapplied workspace background changes");
         } else { auto layout = current_layout(); layout["mode"] = id; store_layout(layout); }
         show_layout();
     });
-    reload.signal_clicked().connect([this] { refresh(); });
+    reload.signal_clicked().connect([this] { refresh(true); });
     apply.signal_clicked().connect([this] { save(); });
     all.signal_clicked().connect([this]
     {
@@ -63,29 +91,43 @@ BackgroundsPage::BackgroundsPage(const std::string& config) : Gtk::Box(Gtk::ORIE
         if (target.is_null()) target = {{"default", empty_layout()}, {"workspaces", json::object()}};
         for (int y=0; y<output["grid"][1]; ++y) for (int x=0; x<output["grid"][0]; ++x)
             target["workspaces"][std::to_string(x)+","+std::to_string(y)] = layout;
-        changed(); show_layout();
+        ++edit_serial; changed(); status.set_text("Unapplied workspace background changes"); show_layout();
     });
-    refresh();
+    signal_map().connect([this] { if (pending_job) check_job(); else if (!available) refresh(); });
+    signal_unmap().connect([this] { refresh_pending = discard_pending = false; ipc.cancel_observation(); });
+    refresh(); changed();
     timer = Glib::signal_timeout().connect([this]
     {
-        if (pending_job)
-        {
-            try
-            {
-                auto next = request("workspace-backgrounds/status");
-                show_memory(next);
-                if (next["completed_job"].get<uint64_t>() == pending_job)
-                {
-                    pending_job = 0;
-                    if (next["job_success"].get<bool>()) refresh();
-                    else { changed(); status.set_text(next["error_message"].get<std::string>()); }
-                }
-            } catch (const std::exception& e) { pending_job = 0; changed(); status.set_text(e.what()); }
-        }
+        if (pending_job && get_mapped() && !ipc.busy()) check_job();
         return true;
     }, 200);
 }
 BackgroundsPage::~BackgroundsPage() { timer.disconnect(); }
+
+void BackgroundsPage::check_job()
+{
+    if (!pending_job || ipc.busy()) return;
+    ipc.send("workspace-backgrounds/status", {}, [this] (WcmIpcResult result)
+    {
+        try
+        {
+            if (!result.error.empty()) throw std::runtime_error(result.error);
+            auto next = json::parse(result.reply.serialize());
+            show_memory(next);
+            if (next["completed_job"].get<uint64_t>() == pending_job)
+            {
+                pending_job = 0;
+                if (next["job_success"].get<bool>()) refresh(true);
+                else { changed(); status.set_text(next["error_message"].get<std::string>()); }
+            }
+        } catch (const std::exception& e)
+        {
+            // This is an observation failure, not evidence that the submitted
+            // renderer job failed. Retain its id and never resubmit the job.
+            status.set_text(std::string(e.what()) + "; still waiting for the background job.");
+        }
+    });
+}
 void BackgroundsPage::show_memory(const json& renderer)
 {
     const auto mib = 1024 * 1024;
@@ -94,14 +136,31 @@ void BackgroundsPage::show_memory(const json& renderer)
     memory.set_text("Image memory: " + std::to_string((used + mib - 1) / mib) + " / " +
         std::to_string(limit / mib) + " MiB. Adjustable in Workspace backgrounds → Texture budget.");
 }
-void BackgroundsPage::refresh()
+void BackgroundsPage::refresh(bool discard)
 {
-    try
+    if (discard) discard_serial = edit_serial;
+    if (mutation_pending || pending_job) return;
+    if (ipc.busy()) { refresh_pending = true; discard_pending |= discard; return; }
+    refresh_pending = false; discard |= discard_pending; discard_pending = false;
+    auto serial = discard ? discard_serial : edit_serial;
+    status.set_text("Waiting for workspace backgrounds…");
+    ipc.send("workspace-backgrounds/get", {}, [this, discard, serial] (WcmIpcResult result)
     {
-        auto next = request("workspace-backgrounds/get");
+        try
+        {
+            if (!result.error.empty()) throw std::runtime_error(result.error);
+            auto next = json::parse(result.reply.serialize());
         if (next["version"] != 1) throw std::runtime_error("Unsupported workspace background API");
         if (std::filesystem::weakly_canonical(next["config_file"].get<std::string>()) != std::filesystem::weakly_canonical(config_file))
             throw std::runtime_error("Open WCM with the running session's configuration to edit workspace backgrounds");
+        validate_background_snapshot(next);
+        if (serial != edit_serial || (!discard && available && draft != original))
+        {
+            show_memory(next); status.set_text("Unapplied workspace background changes retained.");
+            if (refresh_pending && get_mapped()) refresh();
+            return;
+        }
+        uncertain = false;
         state = next; draft = original = state["settings"]; available = true;
         show_memory(state);
         loading = true; outputs.remove_all();
@@ -110,12 +169,14 @@ void BackgroundsPage::refresh()
         loading = false; select_output();
         auto error = state["error_message"].get<std::string>();
         status.set_text(!error.empty() ? error : state["applied"].get<bool>() ? "Saved and loaded by the workspace renderer" : "Saved; images are awaiting the workspace renderer");
-    } catch (const std::exception& e)
-    {
-        available = false; loading = false;
-        status.set_text(std::string(e.what()) + "\nWorkspace images need the workspace-backgrounds and ipc plugins with the matching Wayfire build.");
-    }
-    changed();
+        } catch (const std::exception& e)
+        {
+            loading = false; changed();
+            status.set_text(std::string(e.what()) + " Last observed settings and unapplied edits are retained.");
+        }
+        changed();
+        if (refresh_pending && get_mapped()) refresh();
+    });
 }
 void BackgroundsPage::select_output()
 {
@@ -143,15 +204,14 @@ void BackgroundsPage::store_layout(const json& layout)
     auto& target = draft["profiles"][profile];
     if (target.is_null()) target = {{"default", empty_layout()}, {"workspaces", json::object()}};
     if (selected_workspace == "default") target["default"] = layout; else target["workspaces"][selected_workspace] = layout;
-    changed();
+    ++edit_serial; changed(); status.set_text("Unapplied workspace background changes");
 }
 void BackgroundsPage::changed()
 {
-    outputs.set_sensitive(available && !pending_job); selection.set_sensitive(available && !pending_job);
-    mode.set_sensitive(available && !pending_job); editor.set_sensitive(available && !pending_job && mode.get_active_id() != "inherit");
-    apply.set_sensitive(available && !pending_job && draft != original); all.set_sensitive(available && !pending_job);
-    reload.set_sensitive(!pending_job);
-    if (available && draft != original && !pending_job) status.set_text("Unapplied workspace background changes");
+    outputs.set_sensitive(available && !pending_job && !mutation_pending); selection.set_sensitive(available && !pending_job && !mutation_pending);
+    mode.set_sensitive(available && !pending_job && !mutation_pending); editor.set_sensitive(available && !pending_job && !mutation_pending && mode.get_active_id() != "inherit");
+    apply.set_sensitive(available && !pending_job && !mutation_pending && draft != original && !uncertain); all.set_sensitive(available && !pending_job && !mutation_pending);
+    reload.set_sensitive(!pending_job && !mutation_pending);
 }
 void BackgroundsPage::show_layout()
 {
@@ -211,9 +271,25 @@ void BackgroundsPage::image_row(Gtk::Box& parent, const std::string& label, cons
 }
 void BackgroundsPage::save()
 {
-    try
+    if (!available || pending_job || mutation_pending || uncertain || draft == original) return;
+    ipc.cancel_observation(); refresh_pending = discard_pending = false;
+    json request = {{"revision",state["revision"]}, {"topology",state["topology"]}, {"settings",draft}};
+    wf::json_t input; wf::json_t::parse_string(request.dump(), input);
+    mutation_pending = true; changed(); status.set_text("Submitting workspace background changes…");
+    ipc.send("workspace-backgrounds/apply", input, [this] (WcmIpcResult result)
     {
-        auto response = request("workspace-backgrounds/apply", {{"revision",state["revision"]}, {"topology",state["topology"]}, {"settings",draft}});
-        pending_job = response["job"]; status.set_text("Preparing workspace background images…"); changed();
-    } catch (const std::exception& e) { status.set_text(e.what()); }
+        mutation_pending = false;
+        try
+        {
+            if (!result.error.empty()) throw std::runtime_error(result.error);
+            auto response = json::parse(result.reply.serialize());
+            pending_job = response.at("job").get<uint64_t>();
+            if (!pending_job) throw std::runtime_error("Invalid background job response");
+            changed(); status.set_text("Preparing workspace background images…");
+        } catch (const std::exception& e)
+        {
+            uncertain = result.uncertain || result.error.empty(); changed();
+            status.set_text(std::string(e.what()) + (uncertain ? ". Outcome unknown; use Revert workspace changes to reload the saved state before applying again." : ""));
+        }
+    }, true);
 }
diff --git a/src/backgrounds.hpp b/src/backgrounds.hpp
index be75561..d7a2a8d 100644
--- a/src/backgrounds.hpp
+++ b/src/backgrounds.hpp
@@ -1,5 +1,6 @@
 #pragma once
 #include <gtkmm.h>
+#include "ipc.hpp"
 #include <nlohmann/json.hpp>
 
 class BackgroundsPage : public Gtk::Box
@@ -14,11 +15,14 @@ class BackgroundsPage : public Gtk::Box
     Gtk::Button apply{"Apply workspace backgrounds"}, reload{"Revert workspace changes"}, all{"Copy to all workspaces"};
     json state, draft, original;
     std::string config_file, selected_output, selected_workspace = "default";
-    bool loading = false, available = false;
+    bool loading = false, available = false, mutation_pending = false, uncertain = false;
+    bool refresh_pending = false, discard_pending = false;
+    uint64_t edit_serial = 0, discard_serial = 0;
+    WcmIpcClient ipc;
     uint64_t pending_job = 0;
     sigc::connection timer;
-    static json request(const std::string& method, const json& data = json::object());
-    void refresh();
+    void refresh(bool discard = false);
+    void check_job();
     void show_memory(const json& renderer);
     void select_output();
     void show_layout();
diff --git a/src/displays.cpp b/src/displays.cpp
index 0ea8993..ecb50f6 100644
--- a/src/displays.cpp
+++ b/src/displays.cpp
@@ -2,6 +2,8 @@
 #include "displays.hpp"
 #include "backgrounds.hpp"
 #include "ipc.hpp"
+#include <nlohmann/json.hpp>
+#include <cmath>
 #include <gtk-layer-shell.h>
 #include <wayfire/config/types.hpp>
 #include <sys/socket.h>
@@ -40,9 +42,40 @@ void field(Gtk::Grid& grid, int row, const std::string& name, Gtk::Widget& contr
 }
 }
 
-wf::json_t DisplaysPage::request(const std::string& method, wf::json_t data)
+namespace
+{
+void validate_display_snapshot(const wf::json_t& wire)
 {
-    return wcm_ipc_request(method, data);
+    // Validate everything load()/select_monitor() consume before replacing a
+    // last-good observation or rebuilding any draft controls.
+    auto data = nlohmann::json::parse(wire.serialize());
+    data.at("revision").get<std::string>(); data.at("pending").get<bool>();
+    const auto& options = data.at("options");
+    if (!options.is_object()) throw std::runtime_error("Invalid display options");
+    for (const auto& value : options) value.get<std::string>();
+    for (auto key : {"core/window_scope_rules", "core/window_scope", "core/stitch_enabled", "core/stitch_outputs",
+        "core/default_output", "grid/use_virtual", "grid/use_physical", "grid/reset_scope", "grid/next_monitor",
+        "grid/zone_shift", "grid/zone_maximize", "move/activate_zone"}) options.at(key).get<std::string>();
+    std::stoi(options.at("grid/zone_gap").get<std::string>());
+    auto rules = nlohmann::json::parse(options.at("core/window_scope_rules").get<std::string>());
+    if (!rules.is_array()) throw std::runtime_error("Invalid application scope rules");
+    for (auto& rule : rules) { rule.at("app_id").get<std::string>(); rule.at("scope").get<std::string>(); }
+    if (!data.at("physical").is_array()) throw std::runtime_error("Invalid physical monitor list");
+    std::set<std::string> names;
+    for (auto& head : data.at("physical"))
+    {
+        auto name = head.at("name").get<std::string>();
+        if (name.empty() || !names.insert(name).second) throw std::runtime_error("Invalid monitor name");
+        auto prefix = head.at("prefix").get<std::string>(); head.at("description").get<std::string>();
+        for (auto key : {"width", "height", "refresh"}) head.at(key).get<int>();
+        if (!head.at("modes").is_array()) throw std::runtime_error("Invalid monitor modes");
+        for (auto& mode : head.at("modes")) for (auto key : {"width", "height", "refresh"}) mode.at(key).get<int>();
+        for (auto key : {"mode", "masked", "position", "transform"}) options.at(prefix + key).get<std::string>();
+        std::stoi(options.at(prefix + "zone_gap").get<std::string>());
+        auto scale = std::stod(options.at(prefix + "scale").get<std::string>());
+        if (!std::isfinite(scale) || scale <= 0) throw std::runtime_error("Invalid monitor scale");
+    }
+}
 }
 
 DisplaysPage::DisplaysPage(const std::string& config, std::function<void()> on_saved,
@@ -166,6 +199,8 @@ DisplaysPage::DisplaysPage(const std::string& config, std::function<void()> on_s
         std::swap(order[i], order[target]); update_members(); changed();
     };
     left_button.signal_clicked().connect([move] { move(-1); }); right_button.signal_clicked().connect([move] { move(1); });
+    signal_map().connect([this] { refresh(); });
+    signal_unmap().connect([this] { leave(); });
     refresh(true);
     timer = Glib::signal_timeout().connect([this]
     {
@@ -173,16 +208,27 @@ DisplaysPage::DisplaysPage(const std::string& config, std::function<void()> on_s
         {
             --countdown;
             status.set_text("Keep these display settings? Reverting automatically in " + std::to_string(std::max(0, countdown)) + " seconds.");
-            if (countdown <= 0) { transaction.clear(); refresh(true); status.set_text("Display preview expired; previous settings restored."); }
-        } else if (get_mapped() && !dirty) refresh();
+            if (countdown <= 0 && !mutation_pending) { transaction.clear(); refresh(); status.set_text("Display preview deadline reached; checking current settings."); }
+        } else if (get_mapped() && (!dirty || uncertain)) refresh();
         return true;
     }, 1000);
 }
 
 DisplaysPage::~DisplaysPage()
 {
-    timer.disconnect(); identify_timer.disconnect();
-    if (!transaction.empty()) { try { wf::json_t data; data["token"] = transaction; request("displays/revert", data); } catch (...) {} }
+    timer.disconnect(); identify_timer.disconnect(); ipc.cancel_observation();
+    if (!transaction.empty())
+    {
+        wf::json_t data; data["token"] = transaction;
+        wcm_ipc_cleanup("displays/revert", data);
+    }
+}
+
+void DisplaysPage::leave()
+{
+    refresh_pending = discard_pending = false;
+    ipc.cancel_observation(); identify_timer.disconnect(); identifiers.clear();
+    if (!transaction.empty() && !mutation_pending) finish(false);
 }
 
 std::string DisplaysPage::get(const std::string& key) const
@@ -194,28 +240,71 @@ void DisplaysPage::error(const std::string& message) { status.set_text(message);
 
 void DisplaysPage::refresh(bool discard)
 {
-    try
+    if (discard) discard_serial = edit_serial;
+    if (mutation_pending) return;
+    if (ipc.busy()) { refresh_pending = true; discard_pending |= discard; return; }
+    refresh_pending = false; discard |= discard_pending; discard_pending = false;
+    auto serial = discard ? discard_serial : edit_serial;
+    status.set_text("Waiting for display settings…");
+    ipc.send("displays/get", {}, [this, discard, serial] (WcmIpcResult result)
     {
-        auto data = request("displays/get");
-        if (data["version"].as_int() != 1) throw std::runtime_error("Unsupported display-management version");
-        if (std::filesystem::weakly_canonical(data["config_file"].as_string()) != std::filesystem::weakly_canonical(config_file))
-            throw std::runtime_error("WCM is editing a different configuration from the running compositor. Open its session configuration: " + data["config_file"].as_string());
-        if (data["pending"].as_bool() && transaction.empty())
+        try
         {
-            left.set_sensitive(false); right.set_sensitive(false); scope_tab.set_sensitive(false);
-            apply_button.set_sensitive(false); identify_button.set_sensitive(false);
-            status.set_text("A display preview is awaiting confirmation in another window."); return;
+            if (!result.error.empty()) throw std::runtime_error(result.error);
+            auto data = result.reply;
+            if (data["version"].as_int() != 1) throw std::runtime_error("Unsupported display-management version");
+            if (std::filesystem::weakly_canonical(data["config_file"].as_string()) != std::filesystem::weakly_canonical(config_file))
+                throw std::runtime_error("WCM is editing a different configuration from the running compositor. Open its session configuration: " + data["config_file"].as_string());
+            validate_display_snapshot(data);
+            foreign_preview = data["pending"].as_bool() && transaction.empty();
+            if (foreign_preview)
+            {
+                update_controls();
+                status.set_text(uncertain ? "The previous request has an uncertain outcome. A preview is pending; waiting for its automatic rollback." :
+                    "A display preview is awaiting confirmation in another window.");
+            } else
+            {
+                uncertain = false;
+                // A refresh can discard only the draft that existed when it
+                // started. Never overwrite typing done while its reply waited.
+                if (serial == edit_serial && (discard || !dirty) && (discard || revision != data["revision"].as_string())) load(data);
+                available = true; update_controls();
+                status.set_text(dirty ? "Unapplied changes retained. Apply checks the current configuration revision." :
+                    "Changes are previewed for 20 seconds. Keep Changes saves them; leaving this page reverts the preview.");
+            }
+        } catch (const std::exception& e)
+        {
+            loading = false; update_controls();
+            error(std::string(e.what()) + " Last observed settings and unapplied edits are retained.");
         }
-        bool recovering = !available;
-        if (discard || revision != data["revision"].as_string()) load(data);
-        available = true; update_controls();
-        if (recovering && !dirty) status.set_text("Changes are previewed for 20 seconds. Keep Changes saves them; closing WCM lets the preview revert.");
-    } catch (const std::exception& e)
+        if (refresh_pending && get_mapped()) refresh();
+    });
+}
+
+void DisplaysPage::refresh_apps()
+{
+    // This optional observation shares the page's single outstanding slot.
+    if (ipc.busy()) return;
+    ipc.send("window-rules/list-views", {}, [this] (WcmIpcResult result)
     {
-        loading = false; available = false; update_controls();
-        error(std::string(e.what()) + "\nDisplays needs the output-control and ipc plugins from the matching Wayfire package.");
-        apply_button.set_sensitive(false);
-    }
+        if (result.error.empty() && result.reply.is_array())
+        {
+            auto selected_app = running_apps.get_active_id();
+            running_apps.remove_all(); std::set<std::string> apps;
+            auto views = result.reply;
+            for (size_t i = 0; i < views.size(); ++i)
+            {
+                wf::json_t view = views[i];
+                if (view["mapped"].as_bool() && view["role"].as_string() == "toplevel")
+                {
+                    auto app = view["app-id"].as_string();
+                    if (!app.empty() && apps.insert(app).second) running_apps.append(app, app);
+                }
+            }
+            if (!running_apps.set_active_id(selected_app)) running_apps.set_active(0);
+        }
+        if (refresh_pending && get_mapped()) refresh();
+    });
 }
 
 void DisplaysPage::load(const wf::json_t& data)
@@ -260,25 +349,11 @@ void DisplaysPage::load(const wf::json_t& data)
                 rule.has_member("scope") && rule["scope"].is_string())
                 append_rule(rule["app_id"].as_string(), rule["scope"].as_string());
         }
-    running_apps.remove_all();
-    try
-    {
-        auto views = request("window-rules/list-views"); std::set<std::string> apps;
-        for (size_t i = 0; i < views.size(); ++i)
-        {
-            wf::json_t view = views[i];
-            if (view["mapped"].as_bool() && view["role"].as_string() == "toplevel")
-            {
-                auto app = view["app-id"].as_string();
-                if (!app.empty() && apps.insert(app).second) running_apps.append(app, app);
-            }
-        }
-        running_apps.set_active(0);
-    } catch (...) {} // Rules remain editable when ipc-rules is disabled.
+    refresh_apps();
     std::istringstream input(get("core/stitch_outputs")); std::string name;
     while (input >> name) if (heads.count(name)) order.push_back(name);
     combined.set_active(get("core/stitch_enabled") == "true");
-    gap.set_value(std::stoi(get("grid/zone_gap"))); shift.set_active(get("move/zone_shift") == "true");
+    gap.set_value(std::stoi(get("grid/zone_gap"))); shift.set_active(get("grid/zone_shift") == "true");
     zone_binding.set_text(get("grid/zone_maximize")); drag_binding.set_text(get("move/activate_zone"));
     update_defaults();
     if (!heads.count(selected)) selected = heads.empty() ? "" : heads.begin()->first;
@@ -334,13 +409,14 @@ void DisplaysPage::update_defaults()
 void DisplaysPage::changed()
 {
     if (loading) return;
+    ++edit_serial;
     set("core/stitch_enabled", combined.get_active() ? "true" : "false");
     set("core/default_output", default_output.get_active_id());
     set("core/window_scope", default_scope.get_active_id());
     set("grid/use_virtual", virtual_binding.get_text()); set("grid/use_physical", physical_binding.get_text());
     set("grid/reset_scope", reset_binding.get_text()); set("grid/next_monitor", next_binding.get_text());
     set("grid/zone_gap", std::to_string(gap.get_value_as_int()));
-    set("move/zone_shift", shift.get_active() ? "true" : "false");
+    set("grid/zone_shift", shift.get_active() ? "true" : "false");
     set("grid/zone_maximize", zone_binding.get_text()); set("move/activate_zone", drag_binding.get_text());
     if (heads.count(selected))
     {
@@ -348,7 +424,10 @@ void DisplaysPage::changed()
         set(pre + "masked", role.get_active_id() == "masked" ? "true" : "false");
         set(pre + "mode", role.get_active_id() == "off" ? "off" : std::string(mode.get_active_id()));
         set(pre + "position", position.get_text());
-        std::ostringstream numeric; numeric << scale.get_value(); set(pre + "scale", numeric.str());
+        if (std::stod(get(pre + "scale")) != scale.get_value())
+        {
+            std::ostringstream numeric; numeric << scale.get_value(); set(pre + "scale", numeric.str());
+        }
         set(pre + "transform", rotation.get_active_id());
         set(pre + "zone_gap", std::to_string(local_gap.get_value_as_int()));
         auto it = std::find(order.begin(), order.end(), selected);
@@ -363,12 +442,14 @@ void DisplaysPage::changed()
 void DisplaysPage::update_controls()
 {
     bool preview = !transaction.empty();
+    bool locked = preview || mutation_pending || foreign_preview || uncertain;
     settings_state.set_visible_child("settings");
     diagram.set_visible(available && settings_tabs.get_current_page() != 3);
-    left.set_sensitive(available && !preview); right.set_sensitive(available && !preview);
-    scope_tab.set_sensitive(available && !preview); refresh_button.set_sensitive(!preview);
-    identify_button.set_sensitive(available && !heads.empty() && !preview);
-    keep_button.set_visible(preview); revert_button.set_visible(preview); apply_button.set_visible(!preview); apply_button.set_sensitive(available && dirty && !preview);
+    left.set_sensitive(available && !locked); right.set_sensitive(available && !locked);
+    scope_tab.set_sensitive(available && !locked); refresh_button.set_sensitive(!preview && !mutation_pending);
+    identify_button.set_sensitive(available && !heads.empty() && !locked);
+    keep_button.set_visible(preview); revert_button.set_visible(preview); apply_button.set_visible(!preview); apply_button.set_sensitive(available && dirty && !locked);
+    keep_button.set_sensitive(!mutation_pending && !uncertain); revert_button.set_sensitive(!mutation_pending);
     bool desktop = role.get_active_id() == "desktop";
     include.set_sensitive(desktop);
     local_gap.set_sensitive(desktop && include.get_active());
@@ -381,30 +462,66 @@ void DisplaysPage::update_controls()
 
 void DisplaysPage::apply()
 {
-    try
+    if (!available || !dirty || mutation_pending || foreign_preview || uncertain || !transaction.empty()) return;
+    ipc.cancel_observation(); refresh_pending = discard_pending = false;
+    wf::json_t options, data;
+    for (auto& [key, value] : draft) if (!original.count(key) || original.at(key) != value) options[key] = value;
+    data["options"] = options; data["revision"] = revision;
+    mutation_pending = true; update_controls(); status.set_text("Waiting for the display preview…");
+    auto started = g_get_monotonic_time();
+    ipc.send("displays/apply", data, [this, started] (WcmIpcResult result)
     {
-        wf::json_t options, data;
-        for (auto& [key, value] : draft) if (!original.count(key) || original.at(key) != value) options[key] = value;
-        data["options"] = options; data["revision"] = revision;
-        auto response = request("displays/apply", data);
-        transaction = response["token"].as_string(); countdown = response["timeout"].as_int();
-        status.set_text("Keep these display settings? They revert automatically in 20 seconds."); update_controls();
-        keep_button.grab_focus();
-    } catch (const std::exception& e) { error(e.what()); }
+        mutation_pending = false;
+        if (!result.error.empty() || !result.reply["token"].is_string() || result.reply["token"].as_string().empty())
+        {
+            uncertain = result.uncertain || result.error.empty();
+            update_controls();
+            error((result.error.empty() ? "Invalid display preview response" : result.error) +
+                (uncertain ? ". Outcome unknown; any unconfirmed preview will revert automatically. Refresh to check." : ""));
+            return;
+        }
+        transaction = result.reply["token"].as_string();
+        countdown = std::max(0, result.reply["timeout"].as_int() - int((g_get_monotonic_time() - started + 999999) / 1000000));
+        if (!get_mapped()) { finish(false); return; }
+        status.set_text("Keep these display settings? They revert automatically after the preview deadline.");
+        update_controls(); keep_button.grab_focus();
+    }, true, [] (WcmIpcResult result)
+    {
+        if (result.reply["token"].is_string() && !result.reply["token"].as_string().empty())
+        {
+            wf::json_t data; data["token"] = result.reply["token"].as_string();
+            wcm_ipc_cleanup("displays/revert", data);
+        }
+    });
 }
 
 void DisplaysPage::finish(bool keep)
 {
-    try
+    if (transaction.empty() || mutation_pending) return;
+    ipc.cancel_observation(); refresh_pending = discard_pending = false;
+    wf::json_t data; data["token"] = transaction;
+    transaction.clear(); mutation_pending = true; update_controls();
+    status.set_text(keep ? "Waiting for display confirmation…" : "Waiting for display rollback…");
+    ipc.send(keep ? "displays/confirm" : "displays/revert", data, [this, keep] (WcmIpcResult result)
     {
-        wf::json_t data; data["token"] = transaction;
-        request(keep ? "displays/confirm" : "displays/revert", data);
-        transaction.clear(); if (keep) saved(); refresh(true);
-        status.set_text(keep ? "Display settings saved." : "Previous display settings restored.");
-    } catch (const std::exception& e)
+        mutation_pending = false;
+        if (!result.error.empty())
+        {
+            uncertain = result.uncertain; update_controls();
+            error(result.error + (uncertain ? ". Outcome unknown; the request was not repeated. Refresh to check." : ""));
+            return;
+        }
+        uncertain = false;
+        if (keep) { dirty = false; saved(); }
+        if (get_mapped()) refresh(keep);
+        update_controls();
+        status.set_text(keep ? "Display settings saved." : "Previous display settings restored; unapplied edits retained.");
+    }, true, [keep, data] (WcmIpcResult result)
     {
-        transaction.clear(); refresh(true); error(e.what());
-    }
+        // An uncertain confirmation may still own a preview. A revert is a
+        // distinct cleanup action, scoped to its token, never a confirm retry.
+        if (keep && !result.error.empty()) wcm_ipc_cleanup("displays/revert", data);
+    });
 }
 
 bool DisplaysPage::draw(const Cairo::RefPtr<Cairo::Context>& cr)
@@ -444,10 +561,15 @@ bool DisplaysPage::draw(const Cairo::RefPtr<Cairo::Context>& cr)
 
 void DisplaysPage::identify()
 {
-    try
+    if (ipc.busy() || mutation_pending) return;
+    identifiers.clear(); identify_timer.disconnect();
+    status.set_text("Waiting to identify displays…");
+    ipc.send("displays/get", {}, [this] (WcmIpcResult result)
     {
-        identifiers.clear(); identify_timer.disconnect();
-        auto live = request("displays/get"); wf::json_t desktops = live["desktops"];
+        try
+        {
+            if (!result.error.empty()) throw std::runtime_error(result.error);
+            wf::json_t desktops = result.reply["desktops"];
         auto display = Gdk::Display::get_default();
         for (size_t i = 0; i < desktops.size(); ++i)
         {
@@ -483,7 +605,9 @@ void DisplaysPage::identify()
             }
         }
         identify_timer = Glib::signal_timeout().connect([this] { identifiers.clear(); return false; }, 3000);
-    } catch (const std::exception& e) { error(e.what()); }
+        } catch (const std::exception& e) { error(e.what()); }
+        if (refresh_pending && get_mapped()) refresh();
+    });
 }
 
 
diff --git a/src/displays.hpp b/src/displays.hpp
index dc5664b..692c6fe 100644
--- a/src/displays.hpp
+++ b/src/displays.hpp
@@ -1,5 +1,6 @@
 #pragma once
 #include <gtkmm.h>
+#include "ipc.hpp"
 #include <wayfire/nonstd/json.hpp>
 #include <map>
 #include <vector>
@@ -48,12 +49,17 @@ class DisplaysPage : public Gtk::Box
     wf::json_t state;
     std::string revision, transaction, selected, config_file;
     bool loading = false, dirty = false, available = false;
+    bool refresh_pending = false, discard_pending = false, mutation_pending = false;
+    bool foreign_preview = false, uncertain = false;
+    uint64_t edit_serial = 0, discard_serial = 0;
+    WcmIpcClient ipc;
     int countdown = 0;
     sigc::connection timer, identify_timer;
     std::vector<std::unique_ptr<Gtk::Window>> identifiers;
     std::function<void()> saved, show_shell, show_zones;
 
-    wf::json_t request(const std::string& method, wf::json_t data = {});
+    void leave();
+    void refresh_apps();
     void refresh(bool discard = false);
     void load(const wf::json_t& data);
     void select_monitor();
diff --git a/src/ipc.cpp b/src/ipc.cpp
new file mode 100644
index 0000000..9414de9
--- /dev/null
+++ b/src/ipc.cpp
@@ -0,0 +1,198 @@
+#include "ipc.hpp"
+#include <gio/gio.h>
+#include <glib-unix.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <unistd.h>
+#include <endian.h>
+#include <cstring>
+#include <cerrno>
+#include <algorithm>
+#include <stdexcept>
+
+namespace
+{
+constexpr size_t max_reply = 4 * 1024 * 1024;
+constexpr unsigned deadline_ms = 3000;
+
+class Request : public std::enable_shared_from_this<Request>
+{
+    int fd = -1;
+    guint io = 0, timeout = 0, initial = 0;
+    GApplication *application = nullptr;
+    std::string path, output, input;
+    size_t sent = 0, received = 0;
+    uint32_t length = 0;
+    bool connecting = false, header = true, done = false;
+    gint64 deadline = 0;
+    WcmIpcClient::Callback callback;
+
+    using Ref = std::shared_ptr<Request>;
+    static void release(gpointer p) { delete static_cast<Ref*>(p); }
+    static void remove(guint& id) { if (id) { auto old = id; id = 0; g_source_remove(old); } }
+    void watch(GIOCondition condition)
+    {
+        remove(io);
+        io = g_unix_fd_add_full(G_PRIORITY_DEFAULT, fd, condition, [](int, GIOCondition, gpointer p) -> gboolean
+        {
+            auto self = *static_cast<Ref*>(p);
+            try { self->advance(); }
+            catch (const std::exception& e) { self->finish({{}, e.what(), self->sent != 0}); }
+            return G_SOURCE_CONTINUE;
+        }, new Ref(shared_from_this()), release);
+    }
+    void connect_socket()
+    {
+        if (path.empty()) throw std::runtime_error("Open WCM from the running Wayfire session (WAYFIRE_SOCKET is missing).");
+        sockaddr_un addr{}; addr.sun_family = AF_UNIX;
+        if (path.size() >= sizeof addr.sun_path) throw std::runtime_error("Wayfire socket path is too long");
+        std::strcpy(addr.sun_path, path.c_str());
+        fd = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0);
+        if (fd < 0) throw std::runtime_error("Cannot open Wayfire socket");
+        if (connect(fd, reinterpret_cast<sockaddr*>(&addr), sizeof addr))
+        {
+            // AF_UNIX EAGAIN means a full backlog, not a pending connection.
+            if (errno != EINPROGRESS) throw std::runtime_error("Cannot connect to Wayfire");
+            connecting = true;
+        }
+        watch(GIOCondition(G_IO_OUT | G_IO_ERR | G_IO_HUP));
+    }
+    void advance()
+    {
+        if (g_get_monotonic_time() >= deadline) throw std::runtime_error("Wayfire request timed out");
+        if (connecting)
+        {
+            int error = 0; socklen_t size = sizeof error;
+            if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &error, &size) || error)
+                throw std::runtime_error("Cannot connect to Wayfire");
+            connecting = false;
+        }
+        if (!sent)
+        {
+            ucred peer{}; socklen_t size = sizeof peer;
+            if (getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &peer, &size) || peer.uid != getuid())
+                throw std::runtime_error("Wayfire socket belongs to another user");
+        }
+        size_t budget = 64 * 1024; // Yield between chunks, even for a fast peer.
+        while (sent < output.size() && budget)
+        {
+            auto n = send(fd, output.data() + sent, std::min(output.size() - sent, budget), MSG_NOSIGNAL);
+            if (n < 0 && errno == EINTR) continue;
+            if (n < 0 && (errno == EAGAIN || errno == EWOULDBLOCK)) return;
+            if (n <= 0) throw std::runtime_error("Wayfire request failed");
+            sent += n; budget -= n;
+        }
+        if (sent < output.size()) return;
+        // Replace the write watch once; the read watch must not spin on OUT.
+        if (input.empty() && header && !received)
+        {
+            input.resize(sizeof length);
+            watch(GIOCondition(G_IO_IN | G_IO_ERR | G_IO_HUP));
+        }
+        while (budget)
+        {
+            auto n = recv(fd, input.data() + received, std::min(input.size() - received, budget), 0);
+            if (n < 0 && errno == EINTR) continue;
+            if (n < 0 && (errno == EAGAIN || errno == EWOULDBLOCK)) return;
+            if (n <= 0) throw std::runtime_error("Wayfire disconnected before replying");
+            received += n; budget -= n;
+            if (received != input.size()) continue;
+            if (header)
+            {
+                std::memcpy(&length, input.data(), sizeof length); length = le32toh(length);
+                if (!length || length > max_reply) throw std::runtime_error("Invalid Wayfire response size");
+                header = false; input.resize(length); received = 0;
+            } else
+            {
+                wf::json_t reply;
+                if (wf::json_t::parse_string(input, reply) || (!reply.is_object() && !reply.is_array()))
+                    throw std::runtime_error("Invalid Wayfire response");
+                if (reply.has_member("error"))
+                {
+                    if (!reply["error"].is_string()) throw std::runtime_error("Invalid Wayfire error response");
+                    finish({reply, reply["error"].as_string(), false});
+                } else finish({reply, {}, false});
+                return;
+            }
+        }
+    }
+    void finish(WcmIpcResult result)
+    {
+        if (done) return;
+        auto self = shared_from_this();
+        done = true; remove(initial); remove(io); remove(timeout);
+        if (fd >= 0) { close(fd); fd = -1; }
+        auto completion = std::move(callback);
+        try { if (completion) completion(std::move(result)); }
+        catch (const std::exception& e) { g_warning("WCM IPC completion: %s", e.what()); }
+        if (application) { g_application_release(application); g_object_unref(application); application = nullptr; }
+    }
+  public:
+    static Ref start(const std::string& method, wf::json_t data, WcmIpcClient::Callback callback, bool mutation)
+    {
+        auto request = std::make_shared<Request>();
+        request->callback = std::move(callback);
+        if (auto path = g_getenv("WAYFIRE_SOCKET")) request->path = path;
+        wf::json_t message; message["method"] = method; message["data"] = data;
+        auto bytes = message.serialize();
+        uint32_t length = htole32(bytes.size());
+        request->output.assign(reinterpret_cast<char*>(&length), sizeof length); request->output += bytes;
+        if (mutation && g_application_get_default())
+        {
+            request->application = G_APPLICATION(g_object_ref(g_application_get_default()));
+            g_application_hold(request->application);
+        }
+        request->deadline = g_get_monotonic_time() + deadline_ms * 1000;
+        request->timeout = g_timeout_add_full(G_PRIORITY_DEFAULT, deadline_ms, [](gpointer p) -> gboolean
+        {
+            auto self = *static_cast<Ref*>(p); self->timeout = 0;
+            self->finish({{}, "Wayfire request timed out", self->sent != 0}); return G_SOURCE_REMOVE;
+        }, new Ref(request), release);
+        request->initial = g_idle_add_full(G_PRIORITY_DEFAULT, [](gpointer p) -> gboolean
+        {
+            auto self = *static_cast<Ref*>(p); self->initial = 0;
+            try { self->connect_socket(); }
+            catch (const std::exception& e) { self->finish({{}, e.what(), false}); }
+            return G_SOURCE_REMOVE;
+        }, new Ref(request), release);
+        return request;
+    }
+    void cancel() { callback = {}; finish({}); }
+};
+}
+
+struct WcmIpcClient::State
+{
+    std::shared_ptr<Request> request;
+    bool mutation = false;
+};
+WcmIpcClient::WcmIpcClient() : state(std::make_shared<State>()) {}
+WcmIpcClient::~WcmIpcClient() { cancel_observation(); }
+bool WcmIpcClient::busy() const { return bool(state->request); }
+void WcmIpcClient::cancel_observation()
+{
+    if (state->request && !state->mutation) { state->request->cancel(); state->request.reset(); }
+}
+bool WcmIpcClient::send(const std::string& method, wf::json_t data, Callback callback, bool mutation, Callback orphan)
+{
+    if (busy()) return false;
+    state->mutation = mutation;
+    std::weak_ptr<State> weak = state;
+    state->request = Request::start(method, data,
+        [weak, callback = std::move(callback), orphan = std::move(orphan)] (WcmIpcResult result)
+        {
+            if (auto current = weak.lock())
+            {
+                current->request.reset();
+                if (callback) callback(std::move(result));
+            } else if (orphan) orphan(std::move(result));
+        }, mutation);
+    return true;
+}
+void wcm_ipc_cleanup(const std::string& method, wf::json_t data)
+{
+    Request::start(method, data, [](WcmIpcResult result)
+    {
+        if (!result.error.empty()) g_warning("WCM cleanup: %s", result.error.c_str());
+    }, true);
+}
diff --git a/src/ipc.hpp b/src/ipc.hpp
index dc6acec..040292f 100644
--- a/src/ipc.hpp
+++ b/src/ipc.hpp
@@ -1,59 +1,37 @@
 #pragma once
 #include <wayfire/nonstd/json.hpp>
-#include <sys/socket.h>
-#include <sys/un.h>
-#include <unistd.h>
-#include <endian.h>
-#include <cstring>
-#include <cerrno>
-#include <stdexcept>
+#include <functional>
+#include <memory>
+#include <string>
 
-inline wf::json_t wcm_ipc_request(const std::string& method, wf::json_t data = {})
+struct WcmIpcResult
 {
-    auto path = getenv("WAYFIRE_SOCKET");
-    if (!path || !*path) throw std::runtime_error("Open WCM from the running Wayfire session (WAYFIRE_SOCKET is missing).");
-    sockaddr_un addr{}; addr.sun_family = AF_UNIX;
-    if (strlen(path) >= sizeof addr.sun_path) throw std::runtime_error("Wayfire socket path is too long");
-    strcpy(addr.sun_path, path);
-    int fd = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0);
-    if (fd < 0) throw std::runtime_error("Cannot open Wayfire socket");
-    try
-    {
-        timeval timeout{3, 0};
-        setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof timeout);
-        setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO, &timeout, sizeof timeout);
-        if (connect(fd, reinterpret_cast<sockaddr*>(&addr), sizeof addr)) throw std::runtime_error("Cannot connect to Wayfire");
-        ucred peer{}; socklen_t size = sizeof peer;
-        if (getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &peer, &size) || peer.uid != getuid()) throw std::runtime_error("Wayfire socket belongs to another user");
-        wf::json_t message; message["method"] = method; message["data"] = data;
-        auto bytes = message.serialize(); uint32_t length = htole32(bytes.size());
-        auto write_all = [&] (const char *p, size_t n)
-        {
-            while (n)
-            {
-                auto r = send(fd, p, n, MSG_NOSIGNAL);
-                if (r < 0 && errno == EINTR) continue;
-                if (r <= 0) throw std::runtime_error("Wayfire request failed");
-                p += r; n -= r;
-            }
-        };
-        auto read_all = [&] (char *p, size_t n)
-        {
-            while (n)
-            {
-                auto r = recv(fd, p, n, 0);
-                if (r < 0 && errno == EINTR) continue;
-                if (r <= 0) throw std::runtime_error("Wayfire did not respond");
-                p += r; n -= r;
-            }
-        };
-        write_all(reinterpret_cast<char*>(&length), sizeof length); write_all(bytes.data(), bytes.size());
-        read_all(reinterpret_cast<char*>(&length), sizeof length); length = le32toh(length);
-        if (length > 4 * 1024 * 1024) throw std::runtime_error("Invalid Wayfire response size");
-        bytes.resize(length); read_all(bytes.data(), length);
-        wf::json_t reply;
-        if (wf::json_t::parse_string(bytes, reply)) throw std::runtime_error("Invalid Wayfire response");
-        if (reply.has_member("error")) throw std::runtime_error(reply["error"].as_string());
-        close(fd); return reply;
-    } catch (...) { close(fd); throw; }
-}
+    wf::json_t reply;
+    std::string error;
+    // A transport failure after sending bytes cannot establish mutation outcome.
+    bool uncertain = false;
+};
+
+// Main-context-only channel. One request at a time; page code coalesces reads.
+// Destruction cancels observations. Mutations finish without touching the page,
+// then run a value-only orphan callback (for preview/overlay cleanup).
+class WcmIpcClient
+{
+  public:
+    using Callback = std::function<void(WcmIpcResult)>;
+    WcmIpcClient();
+    ~WcmIpcClient();
+    WcmIpcClient(const WcmIpcClient&) = delete;
+    WcmIpcClient& operator=(const WcmIpcClient&) = delete;
+    bool busy() const;
+    bool send(const std::string& method, wf::json_t data, Callback callback,
+        bool mutation = false, Callback orphan = {});
+    void cancel_observation();
+  private:
+    struct State;
+    std::shared_ptr<State> state;
+};
+
+// A single bounded, best-effort cleanup, never retried. Holds the application
+// while its window closes so cleanup can finish without blocking GTK.
+void wcm_ipc_cleanup(const std::string& method, wf::json_t data);
diff --git a/src/meson.build b/src/meson.build
index 9eebcf2..de9b8ff 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -10,7 +10,7 @@ layer_shell = dependency('gtk-layer-shell-0')
 dep_list = [xml, gtkmm, wf_config, wf_protos, evdev, xkbregistry, libintl, libfmt, wf_json, layer_shell,
   dependency('nlohmann_json'), dependency('threads')]
 
-sources = files('main.cpp', 'metadata.cpp', 'wcm.cpp', 'utils.cpp', 'displays.cpp', 'backgrounds.cpp', 'move-snap.cpp', 'vendor/wf-json.cpp')
+sources = files('main.cpp', 'metadata.cpp', 'wcm.cpp', 'utils.cpp', 'ipc.cpp', 'displays.cpp', 'backgrounds.cpp', 'move-snap.cpp', 'vendor/wf-json.cpp')
 
 executable(meson.project_name(), sources,
                      install : true,
diff --git a/src/metadata.hpp b/src/metadata.hpp
index 18056b2..3585fb2 100644
--- a/src/metadata.hpp
+++ b/src/metadata.hpp
@@ -66,7 +66,7 @@ struct var_data
     double min;
     double max;
     double precision;
-    hint_type hints;
+    hint_type hints = static_cast<hint_type>(0);
 };
 
 using opt_data = std::variant<int, std::string, double>;
diff --git a/src/move-snap.cpp b/src/move-snap.cpp
index 1eccdef..6e2e305 100644
--- a/src/move-snap.cpp
+++ b/src/move-snap.cpp
@@ -1,5 +1,6 @@
 #include "move-snap.hpp"
 #include "ipc.hpp"
+#include <nlohmann/json.hpp>
 #include <filesystem>
 #include <algorithm>
 #include <cmath>
@@ -7,6 +8,27 @@
 
 namespace
 {
+void validate_snap_snapshot(const wf::json_t& wire)
+{
+    auto data = nlohmann::json::parse(wire.serialize());
+    data.at("enabled").get<bool>();
+    for (auto key : {"edge", "corner", "delay"}) data.at(key).get<int>();
+    auto rectangle = [] (const nlohmann::json& r)
+    {
+        for (auto key : {"x", "y", "width", "height"})
+            if (!std::isfinite(r.at(key).get<double>())) throw std::runtime_error("Invalid snap region geometry");
+    };
+    if (!data.at("monitors").is_array()) throw std::runtime_error("Invalid snap monitor list");
+    for (auto& monitor : data.at("monitors"))
+    {
+        monitor.at("name").get<std::string>(); rectangle(monitor.at("geometry"));
+        if (!monitor.at("regions").is_array()) throw std::runtime_error("Invalid snap regions");
+        for (auto& region : monitor.at("regions"))
+        {
+            region.at("slot").get<std::string>(); rectangle(region.at("geometry")); rectangle(region.at("target"));
+        }
+    }
+}
 struct Rect { double x, y, w, h; };
 Rect rect(const wf::json_t& j)
 {
@@ -69,37 +91,62 @@ MoveSnapPage::MoveSnapPage(const std::string& config, std::function<void(bool,in
     delay.signal_value_changed().connect(sigc::mem_fun(*this, &MoveSnapPage::changed));
     scope.signal_changed().connect([this] { if (!loading) { hovered.clear(); target = {}; update(); } });
     monitor.signal_changed().connect([this] { if (loading) return; hovered.clear(); target = {}; diagram.queue_draw(); });
-    overlay.signal_toggled().connect([this] { if (!loading) update(); });
+    overlay.signal_toggled().connect([this] { if (!loading) { if (overlay.get_active()) update(); else stop_overlay(); } });
     refresh.signal_clicked().connect([this] { update(); });
+    enabled.set_sensitive(false); edge.set_sensitive(false); corner.set_sensitive(false); delay.set_sensitive(false); overlay.set_sensitive(false);
     signal_map().connect([this] { update(); });
-    signal_unmap().connect([this] { stop_overlay(); });
+    signal_unmap().connect([this] { refresh_pending = false; ipc.cancel_observation(); stop_overlay(); });
     poll = Glib::signal_timeout().connect([this] { if (get_mapped() && !delayed_save.connected()) update(); return true; }, 1000);
 }
 
 MoveSnapPage::~MoveSnapPage()
 {
-    delayed_save.disconnect(); poll.disconnect(); stop_overlay();
+    delayed_save.disconnect(); poll.disconnect(); ipc.cancel_observation(); stop_overlay();
 }
 
 void MoveSnapPage::stop_overlay()
 {
-    if (!overlay.get_active()) return;
     loading = true; overlay.set_active(false); loading = false;
-    try { wf::json_t request; request["owner"] = owner; request["visible"] = false; wcm_ipc_request("move/snap-regions",request); } catch (...) {}
+    if (!overlay_owned && !cleanup_pending) return;
+    cleanup_pending = true;
+    if (ipc.busy()) return; // Hide only after a pending show has completed.
+    cleanup_pending = false; overlay_owned = false;
+    wf::json_t data; data["owner"] = owner; data["visible"] = false;
+    ipc.send("move/snap-regions", data, [this] (WcmIpcResult result)
+    {
+        if (!result.error.empty()) status.set_text(result.error + "; the snap overlay lease will expire.");
+        if (refresh_pending && get_mapped()) { refresh_pending = false; update(); }
+    }, true);
 }
 
 void MoveSnapPage::update()
 {
-    try
+    if (!get_mapped()) return;
+    if (ipc.busy()) { refresh_pending = true; return; }
+    if (cleanup_pending) { stop_overlay(); return; }
+    refresh_pending = false;
+    wf::json_t request; auto requested_scope = scope.get_active_id().raw();
+    request["scope"] = requested_scope;
+    bool visible = overlay.get_active();
+    // Ordinary polling is read-only. Showing zones explicitly renews their
+    // compositor lease; a failed renewal turns the toggle off, never retries it.
+    if (visible) { request["owner"] = owner; request["visible"] = true; overlay_owned = true; }
+    auto serial = edit_serial;
+    status.set_text("Waiting for snap zones…");
+    ipc.send("move/snap-regions", request, [this, serial, requested_scope] (WcmIpcResult result)
     {
-        wf::json_t request; request["scope"] = std::string(scope.get_active_id());
-        request["owner"] = owner; request["visible"] = overlay.get_active();
-        auto reply = wcm_ipc_request("move/snap-regions",request);
+        if (cleanup_pending || !get_mapped()) { stop_overlay(); return; }
+        try
+        {
+            if (!result.error.empty()) throw std::runtime_error(result.error);
+            auto reply = result.reply;
+            if (requested_scope != scope.get_active_id()) { update(); return; }
         if (reply["version"].as_int() != 1) throw std::runtime_error("This compositor's snap-zone interface is not supported.");
         if (std::filesystem::weakly_canonical(reply["config_file"].as_string()) != std::filesystem::weakly_canonical(config_file))
             throw std::runtime_error("Open WCM with the running session's configuration to edit snap zones.");
+        validate_snap_snapshot(reply);
         loading = true;
-        if (!delayed_save.connected()) { enabled.set_active(reply["enabled"].as_bool()); edge.set_value(reply["edge"].as_int()); corner.set_value(reply["corner"].as_int()); delay.set_value(reply["delay"].as_int()); }
+        if (serial == edit_serial && !delayed_save.connected()) { enabled.set_active(reply["enabled"].as_bool()); edge.set_value(reply["edge"].as_int()); corner.set_value(reply["corner"].as_int()); delay.set_value(reply["delay"].as_int()); }
         std::vector<std::string> names; auto monitors = reply["monitors"];
         for (size_t i = 0; i < monitors.size(); ++i) names.push_back(monitors[i]["name"].as_string());
         if (names != monitor_names)
@@ -114,17 +161,26 @@ void MoveSnapPage::update()
         status.set_text(reply["enabled"].as_bool() ? "Changes save immediately. Regions include panel space and monitor gaps; select a monitor for a closer view." :
             "Enable Snap to activate drag snapping.");
         diagram.queue_draw();
-    } catch (const std::exception& e)
+        } catch (const std::exception& e)
+        {
+            loading = false; stop_overlay();
+            enabled.set_sensitive(available); edge.set_sensitive(available);
+            corner.set_sensitive(available); delay.set_sensitive(available); overlay.set_sensitive(available);
+            status.set_text(std::string(e.what()) + " Last observed zones and edits are retained. Enable Move and IPC in the running Wayfire session.");
+            diagram.queue_draw();
+        }
+        if (refresh_pending && get_mapped() && !ipc.busy()) { refresh_pending = false; update(); }
+    }, visible, [owner = owner] (WcmIpcResult)
     {
-        loading = false; available = false; stop_overlay();
-        enabled.set_sensitive(false); edge.set_sensitive(false); corner.set_sensitive(false); delay.set_sensitive(false); overlay.set_sensitive(false);
-        status.set_text(std::string(e.what()) + " Enable Move and IPC in the running Wayfire session."); diagram.queue_draw();
-    }
+        wf::json_t data; data["owner"] = owner; data["visible"] = false;
+        wcm_ipc_cleanup("move/snap-regions", data);
+    });
 }
 
 void MoveSnapPage::changed()
 {
     if (loading || !available) return;
+    ++edit_serial;
     delayed_save.disconnect();
     delayed_save = Glib::signal_timeout().connect([this]
     {
diff --git a/src/move-snap.hpp b/src/move-snap.hpp
index 239076f..26e88e4 100644
--- a/src/move-snap.hpp
+++ b/src/move-snap.hpp
@@ -1,5 +1,6 @@
 #pragma once
 #include <gtkmm.h>
+#include "ipc.hpp"
 #include <wayfire/nonstd/json.hpp>
 
 class MoveSnapPage : public Gtk::Box
@@ -19,6 +20,9 @@ class MoveSnapPage : public Gtk::Box
     std::function<void(bool, int, int, int)> save;
     sigc::connection poll, delayed_save;
     bool loading = false, available = false;
+    bool refresh_pending = false, cleanup_pending = false, overlay_owned = false;
+    uint64_t edit_serial = 0;
+    WcmIpcClient ipc;
     double zoom = 1, dx = 0, dy = 0;
     wf::json_t target;
     void update();
diff --git a/src/wcm.cpp b/src/wcm.cpp
index 1327c2b..ed998c0 100644
--- a/src/wcm.cpp
+++ b/src/wcm.cpp
@@ -1517,11 +1517,12 @@ void WCM::set_plugin_enabled(Plugin *plugin, bool enabled)
 
 void WCM::create_main_layout()
 {
-    window->signal_key_press_event().connect([] (GdkEventKey *event)
+    window->signal_key_press_event().connect([this] (GdkEventKey *event)
     {
         if (event->state & GDK_CONTROL_MASK && (event->keyval == GDK_KEY_q))
         {
-            std::exit(0);
+            window->close();
+            return true;
         }
 
         return false;
@@ -1550,7 +1551,7 @@ void WCM::create_main_layout()
     main_left_panel_layout.pack_start(search_entry, false, false);
 
     close_button.property_margin().set_value(10);
-    close_button.signal_clicked().connect([] { std::exit(0); });
+    close_button.signal_clicked().connect([this] { window->close(); });
     main_left_panel_layout.pack_end(close_button, false, false);
 
     output_config_button.property_margin().set_value(10);
diff --git a/src/wcm.hpp b/src/wcm.hpp
index ca53963..c7f5eb1 100644
--- a/src/wcm.hpp
+++ b/src/wcm.hpp
@@ -151,6 +151,7 @@ class OptionWidget : public Gtk::Box
     std::vector<std::unique_ptr<Gtk::Widget>> widgets;
     Gtk::Button reset_button;
     sigc::trackable tracker;
+    WcmIpcClient discovery;
 
     guint int_sb_handle;
     guint animate_sb_handle;