TitleBar Buttons not working in some cases

src/Wpf.Ui/Controls/TitleBar/TitleBarButton.cs

@@ -232,4 +232,39 @@
             ),
         };
     }
+
+    PresentationSource presentationSource = null;
+
+	protected bool IsMouseOverElement(nint lParam)
+	{
+		System.Drawing.Point winPoint;
+		bool gotCursorPos = User32.GetCursorPos(out winPoint);
+
+		if (!gotCursorPos)
+		{
+			int fallbackX = unchecked((short)((long)lParam & 0xFFFF));
+			int fallbackY = unchecked((short)(((long)lParam >> 16) & 0xFFFF));
+			winPoint = new System.Drawing.Point(fallbackX, fallbackY);
+		}
+
+		var screenPoint = new System.Windows.Point(winPoint.X, winPoint.Y);
+
+		presentationSource ??= PresentationSource.FromVisual(this);
+
+		if (presentationSource?.CompositionTarget != null)
+		{
+			screenPoint = presentationSource.CompositionTarget.TransformFromDevice.Transform(screenPoint);
+		}
+
+		var localPoint = this.PointFromScreen(screenPoint);
+
+		var hitTestRect = 
+            new System.Windows.Rect(
+			0,
+			0,
+			this.ActualWidth,
+			this.ActualHeight);
+
+		return hitTestRect.Contains(localPoint);
+	}
 }

src/Wpf.Ui/Interop/User32.cs

@@ -1450,6 +1450,9 @@
     [DllImport(Libraries.User32, SetLastError = true)]
     [return: MarshalAs(UnmanagedType.Bool)]
     public static extern bool GetCursorPos([Out] out WinDef.POINT lpPoint);
+    [DllImport(Libraries.User32, SetLastError = true)]
+	public static extern bool GetCursorPos(out System.Drawing.Point lpPoint);
+
 
     [DllImport(Libraries.User32)]
     public static extern bool UnionRect(out WinDef.RECT rcDst, ref WinDef.RECT rc1, ref WinDef.RECT rc2);