Win32Exception on closing window

I have reports of a bug in our app similar to https://github.com/ControlzEx/ControlzEx/issues/13 :

UnhandledException System.ComponentModel.Win32Exception (0x80004005): The parameter is incorrect
at Microsoft.Windows.Shell.WindowChromeWorker._HandleMoveForRealSize(WM uMsg, IntPtr wParam, IntPtr lParam, Boolean& handled) in d:\projects\git\MahApps.Metro\MahApps.Metro\Microsoft.Windows.Shell\WindowChromeWorker.cs:line 1160
at Microsoft.Windows.Shell.WindowChromeWorker._WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled) in d:\projects\git\MahApps.Metro\MahApps.Metro\Microsoft.Windows.Shell\WindowChromeWorker.cs:line 613
at System.Windows.Interop.HwndSource.PublicHooksFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)

@batzen May you write, please, how have you reproduced the bug for the ControlzEx? May the same fix be applied to the MahApps, too? Thanks.

Environment

• MahApps.Metro v1.3.0
• Visual Studio 2015

[xmedeko]

I would like to have full stacktrace, but we use CSharpAnalytics and it’s bug 39 cuts the stacktrace. (We should switch to some other, maintained project.)

Since the source code of MahApps and ControlzEx seems similar to me in the Microsoft.Windows.Shell namespace, and I have spotted ControlzEx/ControlzEx#13 and that the fix ControlzEx/ControlzEx@ea4c41c0fdc428269cbea981eedf7a60a836cabd is not in the MahApps, I thought that MahApps contains same bug as ControlzEx before the fix.

Now, it seems the bug is not exactly the same, so I will try to get more information about it.

[xmedeko]

I’ve probably found the problem. We have the MetroWindow shown fullscreen without decorations:

window.WindowState = WindowState.Maximized;
window.IgnoreTaskbarOnMaximize = true;
window.IsWindowDraggable = false;
window.ShowTitleBar = false;
window.ShowCloseButton = false;
window.ShowMaxRestoreButton = false;
window.ShowMinButton = false;

The user can switch off the fullscreen:

window.IgnoreTaskbarOnMaximize = false;
window.IsWindowDraggable = true;
window.ShowTitleBar = true;
window.ShowCloseButton = true;
window.ShowMaxRestoreButton = true;
window.ShowMinButton = true;

However, during this fullscreen switch off the window is first time a little bit smaller than maximized and in a moment it enlarges to the maximized size. A kind if a transition state. When the user clicks the close button in this transition state, then the exception occurs.