diff --git a/source/Components/AvalonDock/Controls/DragService.cs b/source/Components/AvalonDock/Controls/DragService.cs
index 2b5d18e8..96e6c641 100644
--- a/source/Components/AvalonDock/Controls/DragService.cs
+++ b/source/Components/AvalonDock/Controls/DragService.cs
@@ -196,6 +196,7 @@ internal void UpdateMouseLocation(Point dragPosition)
 					if (_currentDropTarget != null)
 					{
 						_currentWindow.DragEnter(_currentDropTarget);
+						BringWindowToTop2((Window)_currentWindow);
 						return;
 					}
 				});
@@ -278,6 +279,8 @@ internal void Abort()
 
 		private void BringWindowToTop2(Window window)
 		{
+			if (window == null) return;
+
 			Win32Helper.SetWindowPos(new WindowInteropHelper(window).Handle,
 				IntPtr.Zero, 0, 0, 0, 0, Win32Helper.SetWindowPosFlags.IgnoreResize | Win32Helper.SetWindowPosFlags.IgnoreMove | Win32Helper.SetWindowPosFlags.DoNotActivate);
 		}