M.K.

Great! For the moment, I simply unchecked the "show image preview in the windows taskbar" option in the settings dialog.

Hi, the app crashes immediately whenever the mouse hovers over the taskbar icon. Assuming Paint .Net is using an unchanged version of Microsoft's TabbedThumbnailNativeMethods.cs, it looks like the DwmSetIconicThumbnail function is called with an invalid thumbnail bitmap. This exception occurs if the taskbar thumbnail violates the maximum boundaries or has an invalid color depth. "An application typically calls the DwmSetIconicThumbnail function after it receives a WM_DWMSENDICONICTHUMBNAIL message for its window. The thumbnail should not exceed the maximum x-coordinate and y-coordinate that are specified in that message. The thumbnail must also have a 32-bit color depth." https://msdn.microsoft.com/en-us/library/windows/desktop/dd389411(v=vs.85).aspx In this context, it could also be an issue with high DPI, since I encountered several problems with native functions (e.g. getting the correct mouse position on the desktop) in windows forms applications, if the application does not call the SetProcessDPIAware function at startup. The "dpiaware" tag in the manifest file does not cover all scenarios. Exception details: System.ArgumentException: Der Wert liegt außerhalb des erwarteten Bereichs. bei Microsoft.WindowsAPICodePack.Taskbar.TabbedThumbnailNativeMethods.SetIconicThumbnail(IntPtr hwnd, IntPtr hBitmap) in D:\src\pdn\src\SystemLayer\WindowsAPICodePack\Shell\Interop\Taskbar\TabbedThumbnailNativeMethods.cs:Zeile 114. bei Microsoft.WindowsAPICodePack.Taskbar.TaskbarWindowManager.DispatchSendIconThumbnailMessage(Message& m, TaskbarWindow taskbarWindow) in D:\src\pdn\src\SystemLayer\WindowsAPICodePack\Shell\Taskbar\TaskbarWindowManager.cs:Zeile 265. bei Microsoft.WindowsAPICodePack.Taskbar.TaskbarWindowManager.DispatchMessage(Message& m, TaskbarWindow taskbarWindow) in D:\src\pdn\src\SystemLayer\WindowsAPICodePack\Shell\Taskbar\TaskbarWindowManager.cs:Zeile 714. bei Microsoft.WindowsAPICodePack.Taskbar.TabbedThumbnailProxyWindow.WndProc(Message& m) in D:\src\pdn\src\SystemLayer\WindowsAPICodePack\Shell\Taskbar\TabbedThumbnailProxyWindow.cs:Zeile 39. bei System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam) Hopefully I could help you a little bit :-) Kind regards, Michael