fix(fancyzones): Prevent stuck drag state and key swallowing

- Subscribe to EVENT_OBJECT_DESTROY to clean up when dragged window
  dies mid-drag (root cause of microsoft#410)
- Only suppress bare Shift key during drag, not all Shift+key combos
- Require Win+Ctrl+Alt for quickLayoutSwitch during drag
- Tag SwallowKey SendInput with dwExtraInfo

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: crutkas

src/modules/fancyzones/FancyZones/FancyZonesApp.cpp

@@ -93,13 +93,14 @@ void FancyZonesApp::InitHooks()
         }
     }
 
-    std::array<DWORD, 6> events_to_subscribe = {
+    std::array<DWORD, 7> events_to_subscribe = {
         EVENT_SYSTEM_MOVESIZESTART,
         EVENT_SYSTEM_MOVESIZEEND,
         EVENT_OBJECT_NAMECHANGE,
         EVENT_OBJECT_UNCLOAKED,
         EVENT_OBJECT_SHOW,
-        EVENT_OBJECT_CREATE
+        EVENT_OBJECT_CREATE,
+        EVENT_OBJECT_DESTROY
     };
     for (const auto event : events_to_subscribe)
     {

src/modules/fancyzones/FancyZonesLib/FancyZones.cpp

@@ -129,6 +129,13 @@ struct FancyZones : public winrt::implements<FancyZones, IFancyZones, IFancyZone
                 PostMessageW(m_window, WM_PRIV_WINDOWCREATED, wparam, lparam);
             }
             break;
+
+        case EVENT_OBJECT_DESTROY:
+            if (data->idObject == OBJID_WINDOW)
+            {
+                PostMessageW(m_window, WM_PRIV_WINDOWDESTROYED, wparam, lparam);
+            }
+            break;
         }
     }
 
@@ -342,9 +349,12 @@ void FancyZones::MoveSizeEnd()
     if (m_windowMouseSnapper)
     {
         m_windowMouseSnapper->MoveSizeEnd();
-        m_draggingState.Disable();
         m_windowMouseSnapper = nullptr;
     }
+
+    // Always disable dragging state, even if m_windowMouseSnapper was already null.
+    // This prevents stuck drag state when a window is destroyed mid-drag.
+    m_draggingState.Disable();
 }
 
 bool FancyZones::MoveToAppLastZone(HWND window, HMONITOR monitor, GUID currentVirtualDesktop) noexcept
@@ -505,7 +515,9 @@ FancyZones::OnKeyDown(PKBDLLHOOKSTRUCT info) noexcept
 
         bool dragging = m_draggingState.IsDragging();
         bool changeLayoutWhileNotDragging = !dragging && !shift && win && ctrl && alt && digitPressed != -1;
-        bool changeLayoutWhileDragging = dragging && digitPressed != -1;
+        // Require Win+Ctrl+Alt even while dragging to prevent accidental layout switches
+        // when drag state is stuck (root cause of #410 "steals number keys")
+        bool changeLayoutWhileDragging = dragging && win && ctrl && alt && digitPressed != -1;
 
         if (changeLayoutWhileNotDragging || changeLayoutWhileDragging)
         {
@@ -519,7 +531,10 @@ FancyZones::OnKeyDown(PKBDLLHOOKSTRUCT info) noexcept
         }
     }
 
-    if (m_draggingState.IsDragging() && shift)
+    // Only suppress the bare Shift key itself during drag (used for drag-toggle).
+    // Do NOT swallow Shift+<other key> combos - that steals keystrokes from apps.
+    if (m_draggingState.IsDragging() && shift &&
+        (info->vkCode == VK_LSHIFT || info->vkCode == VK_RSHIFT))
     {
         return true;
     }
@@ -699,6 +714,16 @@ LRESULT FancyZones::WndProc(HWND window, UINT message, WPARAM wparam, LPARAM lpa
             auto hwnd = reinterpret_cast<HWND>(wparam);
             WindowCreated(hwnd);
         }
+        else if (message == WM_PRIV_WINDOWDESTROYED)
+        {
+            auto hwnd = reinterpret_cast<HWND>(wparam);
+            // If the destroyed window was being dragged, force-end the drag
+            if (m_windowMouseSnapper && m_windowMouseSnapper->GetDraggedWindow() == hwnd)
+            {
+                Logger::info(L"Window destroyed during drag - forcing MoveSizeEnd");
+                MoveSizeEnd();
+            }
+        }
         else if (message == WM_PRIV_LAYOUT_HOTKEYS_FILE_UPDATE)
         {
             LayoutHotkeys::instance().LoadData();

src/modules/fancyzones/FancyZonesLib/FancyZonesWinHookEventIDs.cpp

@@ -7,6 +7,7 @@ UINT WM_PRIV_MOVESIZEEND;
 UINT WM_PRIV_LOCATIONCHANGE;
 UINT WM_PRIV_NAMECHANGE;
 UINT WM_PRIV_WINDOWCREATED;
+UINT WM_PRIV_WINDOWDESTROYED;
 UINT WM_PRIV_INIT;
 UINT WM_PRIV_VD_SWITCH;
 UINT WM_PRIV_EDITOR;
@@ -30,6 +31,7 @@ void InitializeWinhookEventIds()
         WM_PRIV_LOCATIONCHANGE = RegisterWindowMessage(L"{d56c5ee7-58e5-481c-8c4f-8844cf4d0347}");
         WM_PRIV_NAMECHANGE = RegisterWindowMessage(L"{b7b30c61-bfa0-4d95-bcde-fc4f2cbf6d76}");
         WM_PRIV_WINDOWCREATED = RegisterWindowMessage(L"{bdb10669-75da-480a-9ec4-eeebf09a02d7}");
+        WM_PRIV_WINDOWDESTROYED = RegisterWindowMessage(L"{a1b2c3d4-e5f6-7890-abcd-fancyzones01}");
         WM_PRIV_INIT = RegisterWindowMessage(L"{469818a8-00fa-4069-b867-a1da484fcd9a}");
         WM_PRIV_VD_SWITCH = RegisterWindowMessage(L"{128c2cb0-6bdf-493e-abbe-f8705e04aa95}");
         WM_PRIV_EDITOR = RegisterWindowMessage(L"{87543824-7080-4e91-9d9c-0404642fc7b6}");

src/modules/fancyzones/FancyZonesLib/FancyZonesWinHookEventIDs.h

@@ -5,6 +5,7 @@ extern UINT WM_PRIV_MOVESIZEEND;
 extern UINT WM_PRIV_LOCATIONCHANGE;
 extern UINT WM_PRIV_NAMECHANGE;
 extern UINT WM_PRIV_WINDOWCREATED;
+extern UINT WM_PRIV_WINDOWDESTROYED;
 extern UINT WM_PRIV_INIT; // Scheduled when FancyZones is initialized
 extern UINT WM_PRIV_VD_SWITCH; // Scheduled when virtual desktop switch occurs
 extern UINT WM_PRIV_EDITOR; // Scheduled when the editor exits

src/modules/fancyzones/FancyZonesLib/WindowMouseSnap.h

@@ -13,6 +13,8 @@ class WindowMouseSnap
     static std::unique_ptr<WindowMouseSnap> Create(HWND window, const std::unordered_map<HMONITOR, std::unique_ptr<WorkArea>>& activeWorkAreas, notifications::NotificationUtil* notificationUtil);
     ~WindowMouseSnap();
 
+    HWND GetDraggedWindow() const noexcept { return m_window; }
+
     bool MoveSizeStart(HMONITOR monitor, bool isSnapping);
     void MoveSizeUpdate(HMONITOR monitor, POINT const& ptScreen, bool isSnapping, bool isSelectManyZonesState);
     void MoveSizeEnd();

src/modules/fancyzones/FancyZonesLib/util.cpp

@@ -6,6 +6,7 @@
 #include <common/utils/process_path.h>
 #include <common/utils/window.h>
 #include <common/utils/excluded_apps.h>
+#include <modules/interface/powertoy_module_interface.h>
 
 #include <array>
 #include <complex>
@@ -263,6 +264,7 @@ namespace FancyZonesUtils
         inputKey[0].type = INPUT_KEYBOARD;
         inputKey[0].ki.wVk = key;
         inputKey[0].ki.dwFlags = KEYEVENTF_KEYUP;
+        inputKey[0].ki.dwExtraInfo = PowertoyModuleIface::CENTRALIZED_KEYBOARD_HOOK_DONT_TRIGGER_FLAG;
         SendInput(1, inputKey, sizeof(INPUT));
     }
 }