[FancyZones] Feature to create zone layouts spanning multiple monitors (#5289)

* Added the setting

* Added a property to Editor Settings

This will be used later

* Fixed a bug in the previous commit

* Simplified a method

* Added snapping points to the editor

* Simplified a method in ZoneSet

* Updated ZoneSet testcases

* Add a method to FancyZones / ZoneWindowHost

* Almost works

* The editor now launches, but FZ does not understand the results

* Refactored some code

* Snapping to a zone by dragging seems to work

* Hotkeys seem to work

* Refresh the work area handler after changing settings

* Fixed zones not snapping to monitor edges when moved

* Remove unused method in FancyZones.h

* Fixed an issue with DPI awareness

* Renamed setting to spanZonesAcrossMonitors

* Renamed a function

* Fixed a bug with the magnetic effect

* Fix restoring window positions on layout changes

src/modules/fancyzones/lib/MonitorWorkAreaHandler.cpp

@@ -19,12 +19,23 @@ winrt::com_ptr<IZoneWindow> MonitorWorkAreaHandler::GetWorkArea(const GUID& desk
 
 winrt::com_ptr<IZoneWindow> MonitorWorkAreaHandler::GetWorkArea(HWND window)
 {
-    HMONITOR monitor = MonitorFromWindow(window, MONITOR_DEFAULTTONULL);
     GUID desktopId{};
-    if (monitor && VirtualDesktopUtils::GetWindowDesktopId(window, &desktopId))
+    if (VirtualDesktopUtils::GetWindowDesktopId(window, &desktopId))
     {
-        return GetWorkArea(desktopId, monitor);
+        auto allMonitorsWorkArea = GetWorkArea(desktopId, NULL);
+        if (allMonitorsWorkArea)
+        {
+            // First, check if there's a work area spanning all monitors (signalled by the NULL monitor handle)
+            return allMonitorsWorkArea;
+        }
+        else
+        {
+            // Otherwise, look for the work area based on the window's position
+            HMONITOR monitor = MonitorFromWindow(window, MONITOR_DEFAULTTONULL);
+            return GetWorkArea(desktopId, monitor);
+        }
     }
+
     return nullptr;
 }