This is reproducible when you disable the automation peers by setting the AutomationManager.AutomationMode static property to Disabled.
It happens when you open a new RadWindow dialog (using the ShowDialog method), and the close it. After this, when you interact with the main window (click a button, hover a GridView, etc.) the exception occurs.
The exception is thrown only in the Output pane of Visual Studio and it doesn't cause any harm to the application. You can safely ignore it.
The exception message is "Invalid window handle".
To work this around you can enable the "Enable Just My Code" option in Visual Studio.
Maximizing RadWindow from the header button shows a window with the size of the content if SizeToContent = true. If you maximize with double click on header it is ok.
In WPF browser application it is possible to move the focus of a focused TextBox control inside the RadWindow to the parent page with Shift+Tab keyboard combination
Moving a window fast on low performance machine or between two monitors causes incorrect offset to be applied to the mouse cursor
Popup shows behind RadWindow when using two monitors in Windows XP.
Place Expander as content in RadWindow. Once expanded, the SizeToContent feature stops working as expected. Available in the 2015 Q3 Release.
If you have set SizeToContent of RadWindow to true and you use one of the following options, SizeToContent will not work. - UseLayoutRounding = true - TextOptions.SetTextFormattingMode(dialog, TextFormattingMode.Display); Available in the 2015 Q3 Release.
This can be observed only when AllowTransparance is set to false.
If RadWindow has its Width set to a value greater that 50% of the screen and that window is snapped to the left or right, performing minimize and then restore leads to incorrect normal size . Available in LIB version 2015.3.1123, it will be also available in the 2016 Q1 release.
1) Open WPF Demos and maximize it 2) Open "Alert, Prompt and Confirm" sample 3) Click "Confirm" 4) Minimize all windows (for example, by using Win+D) 5) Switch to WPF Demos again 6) Now you can't do anithing with the window, even close it. You can use task manager to close it.
It happens when IsRestrictedWhenMaximized set to true.
When EventBinding is used in XAML to bind commands to events of Window or RadRibbonWindow (as it inherits Window), InvalidOperationException is thrown in design-time. Workarounds: 1. Attach an event handler directly to the events of the Window (RadRibbonWindow) 2. (more MVVM-friendly) use Behavior to attach the appropriate event handler.