Fix Settings window going off-screen after disconnecting 4K monitor

- Fix IsPositionValid to use SystemParameters.VirtualScreen* (DIP units)
  instead of MonitorInfo.WorkingArea (physical pixels) to avoid DPI
  coordinate mismatch on high-DPI and mixed-DPI multi-monitor setups.

- Fix AdjustWindowPosition and SetWindowPosition to correctly calculate
  the max boundary as VirtualScreenTop + VirtualScreenHeight - ActualHeight
  (was VirtualScreenHeight - ActualHeight), which incorrectly allowed
  windows to extend beyond the bottom/right edge when VirtualScreenTop
  or VirtualScreenLeft were non-zero (e.g., monitors above/left of primary).

Co-authored-by: VictoriousRaptor <10308169+VictoriousRaptor@users.noreply.github.com>

Author: Copilot

Flow.Launcher/SettingWindow.xaml.cs

@@ -179,8 +179,8 @@ private void SetWindowPosition(double top, double left)
         // Ensure window does not exceed screen boundaries
         top = Math.Max(top, SystemParameters.VirtualScreenTop);
         left = Math.Max(left, SystemParameters.VirtualScreenLeft);
-        top = Math.Min(top, SystemParameters.VirtualScreenHeight - ActualHeight);
-        left = Math.Min(left, SystemParameters.VirtualScreenWidth - ActualWidth);
+        top = Math.Min(top, SystemParameters.VirtualScreenTop + SystemParameters.VirtualScreenHeight - ActualHeight);
+        left = Math.Min(left, SystemParameters.VirtualScreenLeft + SystemParameters.VirtualScreenWidth - ActualWidth);
 
         Top = top;
         Left = left;
@@ -191,23 +191,19 @@ private void AdjustWindowPosition(ref double top, ref double left)
         // Adjust window position if it exceeds screen boundaries
         top = Math.Max(top, SystemParameters.VirtualScreenTop);
         left = Math.Max(left, SystemParameters.VirtualScreenLeft);
-        top = Math.Min(top, SystemParameters.VirtualScreenHeight - ActualHeight);
-        left = Math.Min(left, SystemParameters.VirtualScreenWidth - ActualWidth);
+        top = Math.Min(top, SystemParameters.VirtualScreenTop + SystemParameters.VirtualScreenHeight - ActualHeight);
+        left = Math.Min(left, SystemParameters.VirtualScreenLeft + SystemParameters.VirtualScreenWidth - ActualWidth);
     }
 
     private static bool IsPositionValid(double top, double left)
     {
-        foreach (var screen in MonitorInfo.GetDisplayMonitors())
-        {
-            var workingArea = screen.WorkingArea;
-
-            if (left >= workingArea.Left && left < workingArea.Right &&
-                top >= workingArea.Top && top < workingArea.Bottom)
-            {
-                return true;
-            }
-        }
-        return false;
+        // Use SystemParameters (DIP units) to match the coordinate system of Window.Top/Left.
+        // MonitorInfo.WorkingArea uses physical pixels which can differ from DIP units when DPI
+        // scaling is active, leading to incorrect results on high-DPI or mixed-DPI setups.
+        return left >= SystemParameters.VirtualScreenLeft &&
+               left < SystemParameters.VirtualScreenLeft + SystemParameters.VirtualScreenWidth &&
+               top >= SystemParameters.VirtualScreenTop &&
+               top < SystemParameters.VirtualScreenTop + SystemParameters.VirtualScreenHeight;
     }
 
     private double WindowLeft()