diff --git a/source/Components/AvalonDock/Controls/LayoutDocumentFloatingWindowControl.cs b/source/Components/AvalonDock/Controls/LayoutDocumentFloatingWindowControl.cs
index b88c016c..8cb81a9d 100644
--- a/source/Components/AvalonDock/Controls/LayoutDocumentFloatingWindowControl.cs
+++ b/source/Components/AvalonDock/Controls/LayoutDocumentFloatingWindowControl.cs
@@ -1,4 +1,4 @@
-/************************************************************************
+/************************************************************************
    AvalonDock
 
    Copyright (C) 2007-2013 Xceed Software Inc.
@@ -16,6 +16,7 @@ This program is provided to you under the terms of the Microsoft Public
 using System.Windows;
 using System.Windows.Controls.Primitives;
 using System.Windows.Input;
+using System.Windows.Interop;
 
 namespace AvalonDock.Controls
 {
@@ -142,6 +143,17 @@ protected override IntPtr FilterMessage(IntPtr hwnd, int msg, IntPtr wParam, Int
 							WindowChrome.GetWindowChrome(this).ShowSystemMenu = false;
 					}
 					break;
+
+				case Win32Helper.WM_CLOSE:
+					if (CloseInitiatedByUser)
+					{
+						// We want to force the window to go through our standard logic for closing.
+						// So, if the window close is initiated outside of our code (such as from the taskbar),
+						// we cancel that close and trigger our close logic instead.
+						this.CloseWindowCommand.Execute(null);
+						handled = true;
+					}
+					break;
 			}
 			return base.FilterMessage(hwnd, msg, wParam, lParam, ref handled);
 		}
diff --git a/source/Components/AvalonDock/Win32Helper.cs b/source/Components/AvalonDock/Win32Helper.cs
index ce2cc9dc..607db494 100644
--- a/source/Components/AvalonDock/Win32Helper.cs
+++ b/source/Components/AvalonDock/Win32Helper.cs
@@ -1,4 +1,4 @@
-/************************************************************************
+/************************************************************************
    AvalonDock
 
    Copyright (C) 2007-2013 Xceed Software Inc.
@@ -153,6 +153,7 @@ internal class WINDOWPOS
 		internal const int WM_INITMENUPOPUP = 0x0117;
 		internal const int WM_KEYDOWN = 0x0100;
 		internal const int WM_KEYUP = 0x0101;
+		internal const int WM_CLOSE = 0x10;
 
 		internal const int WA_INACTIVE = 0x0000;