Last Updated: 02 Sep 2022 14:08 by ADMIN
Release R3 2022
When using Windows 11 build 22000.795 the Acrylic effect does not apply.
Last Updated: 24 Jun 2022 11:35 by Bruno
Double-taping on the corner of the window multiple times displays a gray border. At this point, minimizing the main window results in a blurred rectangle remaining where the RadWindow used to be.
Last Updated: 25 Apr 2022 08:53 by ADMIN
Release R2 2020 SP1

If the autohiding feature of the taskbar is enabled and RadWindow is maximized, the taskbar is not displayed when the mouse is over the bottom of the screen.

This is observed also in RadTabbedWindow.

Last Updated: 15 Oct 2021 11:40 by ADMIN
Created by: Christian
Comments: 0
Category: Window
Type: Feature Request
Support the Snap Layout feature of Windows 11.
Last Updated: 10 Aug 2021 12:57 by ADMIN
Created by: Simon
Comments: 3
Category: Window
Type: Feature Request


our company is slowly rolling out high-DPI laptops to our users. On such devices, Windows automatically enables DPI scaling, using a value of 125% or 150%, depending on the screen's resolution. In combination with an external (unscaled) monitor, this causes our application, to appear blurry on the scaled screen.

Windows has built-in functionality to reduce the blurring, however, this only works on the main screen. If you connect a secondary screen and set that as your main screen, the application will always appear blurry on the laptop screen.

My understanding of the topic is that WPF is DPI aware - but on the system level. So it does not cope well with monitors that have different DPI settings. However, I found a tutorial on Microsoft Docs (, hinting that it is possible to make WPF windows per-monitor DPI aware. Unfortunately, this workaround requires you to inherit your window class from their utility class.

Since all of our windows already inherit from RadWindow, I have no chance to include this without copying either their base class or RadWindow. Having RadWindow support per-monitor DPI awareness would be a great feature to have. Or is there already a way to support this?


Best Regards,

Simon M├╝ller

Hofmann F├Ârdertechnik GmbH


PS: Why does the first feature form in the feature request workflow (the one, where it first searches for similar requests) not let me select the control/area I am searching for like the one for private tickets? I almost submitted this request for the Area "All (Multiple Controls)" because of that.

Won't Fix
Last Updated: 16 Jun 2021 14:03 by ADMIN
When the RadWindow is declared in XAML and is used as a main window, it won't show in the designer by simply merging the required theme resources and defining an implicit style based on the RadWindowStyle.

Tested with 16.8.4 - works as expected. Updated to 16.9.0 to match the client's setup and managed to reproduce the issue. The issue is reproducible also with the 16.10.0 version of Visual Studio.

Last Updated: 11 Jun 2021 12:05 by ADMIN
Release R2 2021 SP
When the value of the IsTopMost property of a RadWindow is changed during runtime and then another RadWindow is shown, an ArgumentOutOfRangeException is thrown.
Last Updated: 21 May 2021 10:19 by ADMIN
Release LIB 2021.2.525 (25/05/2021)

If you open the window on a specific resolution, maximize it and then change the resolution to a bigger one, the window size is not updated. The window stays in the original resolution of the screen.

To work this around subscribe to the SystemEvents.DisplaySettingsChanged event and reset the WindowState of RadWindow.

public MainWindow() // where MainWindow is RadWindow
	SystemEvents.DisplaySettingsChanged += SystemEvents_DisplaySettingsChanged;

private void SystemEvents_DisplaySettingsChanged(object sender, EventArgs e)
	if (this.WindowState == WindowState.Maximized)
		this.WindowState = WindowState.Normal;
		this.WindowState = WindowState.Maximized;

Last Updated: 21 May 2021 10:19 by ADMIN
Release LIB 2021.2.525 (25/05/2021)
The window is not correctly resized when it is maximized and the taskbar is moved from vertical to horizontal or vice versa 
Last Updated: 21 May 2021 06:38 by ADMIN
Release LIB 2021.2.525 (25/05/2021)
Setting the dpiAware attribute to True in the app.manifest file is making the WPF application DPI aware. In this case, the resizing of RadWindow doesn't work properly on two monitors with different DPI scale factors.
Last Updated: 07 Apr 2021 10:38 by ADMIN


Please see attached project,

After use animation changed window size and use the mouse to drag to change the size of the window,

When the window size is smaller than the original size, the upper right button will be hide,

Original WPF Window no this problem, And changing size animation very Smooth then RadWIndow.

Last Updated: 30 Mar 2021 11:30 by ADMIN
We can expose a property/ies to easily customize the header border of the window.
Last Updated: 09 Mar 2021 12:29 by ADMIN
Release LIB 2021.1.315
ArgumentOutOfRangeException can be thrown when showing/closing windows in a multi-threaded application. Here's a possible stack trace:

System.ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index
   at System.ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument argument, ExceptionResource resource)
   at System.ThrowHelper.ThrowArgumentOutOfRangeException()
   at System.Collections.Generic.List`1.RemoveAt(Int32 index)
   at System.Collections.Generic.List`1.Remove(T item)
   at Telerik.Windows.Controls.RadWindowManager.RemoveWindow(WindowBase window)
   at Telerik.Windows.Controls.WindowBase.OnClosed()
   at Telerik.Windows.Controls.RadWindow.OnClosed()
   at Telerik.Windows.Controls.WindowBase.CloseHostImidiately()
   at Telerik.Windows.Controls.WindowBase.TryClose(Boolean shouldCloseHost)
   at Telerik.Windows.Controls.WindowBase.Telerik.Windows.Controls.InternalWindow.IWindowDragAware.TryClose(Boolean shouldCloseHost)
   at Telerik.Windows.Controls.InternalWindow.WindowWithNoChromeWindowHost.OnWindowClosing(Object sender, CancelEventArgs e)
   at System.Windows.Window.OnClosing(CancelEventArgs e)
   at System.Windows.Window.WmClose()
   at System.Windows.Window.WindowFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   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 System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)
   at System.Windows.Threading.Dispatcher.WrappedInvoke(Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)
   at System.Windows.Threading.Dispatcher.LegacyInvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
   at System.Windows.Threading.Dispatcher.Invoke(DispatcherPriority priority, Delegate method, Object arg)
   at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
Last Updated: 10 Feb 2021 13:39 by ADMIN
Last Updated: 10 Feb 2021 13:39 by ADMIN
Created by: Rob A.
Comments: 2
Category: Window
Type: Feature Request

There should be an easy method to add/override the shadow of a RadWindow. Either via XAML attributes or code behind.

It would probably be good to allow the override of BlurRadius, Direction, and ShadowDepth.
For example (mockup):

<telerik:RadWindow x:Class="MyRadWindow"
        Header="Settings" WindowStartupLocation="CenterOwner" SizeToContent="True" ResizeMode="NoResize" MinWidth="500" MaxWidth="900"    DropShadowOverride="True" DropShadowOverrideBlurRadius="10" DropShadowOverrideDirection"-90", DropShadowOverrideDepth="3" DropShadowOverrideColor="White">
    <!-- UI code -->

Last Updated: 01 Feb 2021 06:16 by ADMIN
Release LIB 2021.1.201 (2/1/2021)
Last Updated: 17 Nov 2020 10:39 by ADMIN
As an example Windows 10 OS Window gets different Opacity for its Title and Buttons when Inactive (open two Window-s and make them appear one behind the other -- the one in the background of the active window is inactive). Our Office2016 and Office2016 Touch themes are inspired by Windows 10 OS as we officially stated so we might mind adding this visual appearance on our side for RadWindow.
Last Updated: 05 Nov 2020 15:12 by ADMIN
Release LIB 2020.3.1109 (11/09/2020)
Changing the ResponseButton through the DefaultFocusedButton property of the DialogParameters does not work in the Office2019 theme.
Last Updated: 30 Sep 2020 15:00 by ADMIN
Release LIB 2020.3.1005 (10/05/2020)
Created by: Kalin
Comments: 1
Category: Window
Type: Feature Request
The property is present, but it is not implemented. 
Last Updated: 21 Sep 2020 10:56 by ADMIN
Release LIB 2020.3.921 (09/21/2020)
This behavior can be observed when the ResizeMode property of RadWindow is set to CanResizeWithGrip. 
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