This item is migrated to the Telerik Document Processing portal: 

https://feedback.telerik.com/Project/184/Feedback/Details/190136

Please use the new item for commenting, voting and subscribing instead of this one.

Since the last update, we receive often the following exception from our users log. I don't know exactly how to reproduce, but I know that when it happens, the user tries to click anywhere in the document and each time the exception is thrown. The users need to close and reopen the document to make it work again.

System.NullReferenceException: Object reference not set to an instance of an object. at Telerik.Windows.Documents.UI.DocumentPresenterBase.CaretPosition_PositionChanged(Object sender, EventArgs e) at Telerik.Windows.Documents.DocumentPosition.MoveToPosition(DocumentPosition newPosition) at Telerik.Windows.Documents.Selection.MouseSelectionHandler.UpdateSelectionAndCaretPosition() at Telerik.Windows.Documents.Selection.MouseSelectionHandler.RegisterDocumentMouseMove(Point position, SourceType source) at Telerik.Windows.Documents.UI.DocumentPresenterBase.HandleMouseMoveOnPosition(Point position, SourceType source) at Telerik.Windows.Documents.UI.DocumentPresenterBase.Owner_MouseMove(Object sender, MouseEventArgs e) at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised) at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args) at System.Windows.Input.InputManager.ProcessStagingArea() at System.Windows.Input.MouseDevice.Synchronize() at System.Windows.Input.MouseDevice.PostProcessInput(Object sender, ProcessInputEventArgs e) at System.Windows.Input.InputManager.ProcessStagingArea() at System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawMouseActions actions, Int32 x, Int32 y, Int32 wheel) at System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr hwnd, WindowMessage msg, IntPtr wParam, IntPtr lParam, Boolean& handled) at System.Windows.Interop.HwndSource.InputFilterMessage(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 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)

We also had this case when we try programatically to move the caret (seems to be the same end result exception):

System.NullReferenceException: Object reference not set to an instance of an object.
   at Telerik.Windows.Documents.UI.DocumentPresenterBase.CaretPosition_PositionChanged(Object sender, EventArgs e)
   at Telerik.Windows.Documents.DocumentPosition.MoveToDocumentStart()
   at Telerik.Windows.Documents.DocumentPosition.MoveToFirstPositionInDocument()

When developing live (localization/resource) display language switching for SL5, the LocalizationManager should allow to update all localization strings applied through the ResourceManager. In SL5 it's not possible to listen to an attached dependency property for all dependency objects. Therefore it would help to have a way to know when the attached ResourceKey dependency property changes (and on which DependencyObject) in the LocalizationManager. 

The dialog and the watermark stating that no license is found are displayed, even when the license key is installed properly. This happens in addin projects, like Excel VSTO Add-in.

To workaround this use the  TelerikLicensing.Register method to install your license script key.

public MyWpfUserControl()
{
    TelerikLicensing.Register("your-script-key");
    InitializeComponent();
}

Telerik assemblies needs to be rebuild with a specific key in some redistribution scenarios, so that the assemblies can be bound only to a single WPF application. This is described in the following article: https://docs.telerik.com/devtools/wpf/licensing/protecting-telerik-assembly

Currently, to protect the dlls you need to rebuild the entire source code of Telerik UI for WPF. Sometimes this is not very convenient and it is prompt to errors because several steps should be followed and also few prerequisites should be met.

Consider providing a new mechanism to protect the Telerik assemblies, which is more convenient and gives better protection. 

** Fixed with Telerik.Licensing 1.4.16 **

The build performance with new license validation (2025) is very poor. 2025 version takes about 5 sec. extra time to build. For small projects it takes 10x longer.

Test environment:

1. Default WPF project created from template.
2. Only one change: Nuget Reference in .csproj
3. .NET 8
4. Visual Studio 17.13.

Build times depending on the Version of Telerik Nuget:

<PackageReference Include="Telerik.Windows.Controls.Navigation.for.Wpf" Version="2025.1.211" />

11:25:47:071    Build started at 11:25...
11:25:47:189    1>------ Build started: Project: TelerikBuildTest, Configuration: Debug Any CPU ------
11:25:51:748    1>[Telerik and Kendo UI Licensing]
11:25:51:748    1>      Telerik and Kendo UI License Key found at: C:\Users\...\AppData\Roaming\Telerik\telerik-license.txt (UserDirectory)
11:25:51:748    1>      License issued at 2025-03-16 to e**********@....
11:25:51:748    1>[Telerik and Kendo UI Licensing]
11:25:51:748    1>      Valid Telerik UI for WPF license found.
11:25:52:743    1>[Telerik and Kendo UI Licensing]
11:25:52:743    1>      Telerik and Kendo UI License Key found at: C:\Users\...\AppData\Roaming\Telerik\telerik-license.txt (UserDirectory)
11:25:52:743    1>      License issued at 2025-03-16 to e**********@...
11:25:52:743    1>[Telerik and Kendo UI Licensing]
11:25:52:743    1>      Valid Telerik UI for WPF license found.
11:25:52:815    1>TelerikBuildTest -> C:\Users\....\source\repos\TelerikBuildTest\TelerikBuildTest\bin\Debug\net8.0-windows\TelerikBuildTest.dll
11:25:52:828    ========== Build: 1 succeeded, 0 failed, 0 up-to-date, 0 skipped ==========
11:25:52:828    ========== Build completed at 11:25 and took 05,892 seconds ==========

<PackageReference Include="Telerik.Windows.Controls.Navigation.for.Wpf" Version="2024.4.1213" />

11:26:33:405    Build started at 11:26...
11:26:33:581    1>------ Build started: Project: TelerikBuildTest, Configuration: Debug Any CPU ------
11:26:33:953    1>TelerikBuildTest -> C:\Users\...\source\repos\TelerikBuildTest\TelerikBuildTest\bin\Debug\net8.0-windows\TelerikBuildTest.dll
11:26:33:960    ========== Build: 1 succeeded, 0 failed, 0 up-to-date, 0 skipped ==========
11:26:33:960    ========== Build completed at 11:26 and took 00,633 seconds ==========

Fixed in Telerik.Licensing NuGet package version 1.4.10. Install this (or later) version of the package to avoid the issue.

Build errors may occur in situation where you have two projects one depending on the other, and the main project installs the Telerik.Licensing nuget package. The package triggers a set of MSBuild taks and at some point an IncrementalClean is invoked, which deletes some of the files and errors occur during the build.

The error message that can occur:

CSC : error CS0006: Metadata file 'dll/file/path/here.dll' could not be found [project directory path here]

A XamlParseException is raised when the theme's resource dictionaries are not merged in App.xaml. The missing resource is the RepeatButtonStyle resource.

To work this around, merge the resource dictionaries for the theme in the Resources collection of the App.xaml file.

When trying to install one of the following nuget packages an error occurs:

• Telerik.Windows.Controls.EntityFramework60.for.Wpf.Xaml
  
• Telerik.UI.for.Wpf.AllControls.Xaml (which contains the EF6 package from the previous bullet)

The same issue manifests with the NoXaml version of the same packages.

The error message is:

Severity Code Description Project File Line Suppression State Details
Error Failed to add reference. The package 'Telerik.Windows.Controls.EntityFramework60.for.Wpf.Xaml' tried to add a framework reference to 'EntityFramework' which was not found in the GAC. This is possibly a bug in the package. Please contact the package owners for assistance.
Reference unavailable.

Wrong XAML files are shipped with the Net Core themes archive. Instead of Docuemnts.xaml and RichTextBoxUI.xaml the RichTextBox.xaml file should be added. 

Steps to reproduce: 

1. Download Telerik_UI_for_WPF_Source_[Version].zip

2. Modify the Release70 configuration to Debug70 in the following script - Build_WPF70_Xamlless.bat

3. Execute the bat file to reproduce the error:

Telerik_UI_for_WPF_Source_[Version]\Core\Controls\Input\Touch\TouchManagerV3\TouchManager.TouchMode.cs(242,9): error CS1519: Invalid token '{' in class, record, struct, or interface member declaration [D:\temp\tic\Telerik_UI_for_WPF_Source_2023_3_1114\Core\Controls\Controls_NetCore_5cmyf5ge_wpftmp.csproj::TargetFramework=net7.0-windows]

As I workaround I would suggest editing the NetCoreConfigurations.targets with the following property groups: 

<PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug70|AnyCPU' ">
    <TargetFrameworks>net7.0-windows</TargetFrameworks>
    <PlatformTarget>AnyCPU</PlatformTarget>
    <DebugSymbols>true</DebugSymbols>
    <DebugType>full</DebugType>
    <OutputPath>bin\$(Configuration)\</OutputPath>
    <DefineConstants>DEBUG;WPF;NETCORE;CODE_ANALYSIS;WPF45;WPF40</DefineConstants>
    <TreatWarningsAsErrors>false</TreatWarningsAsErrors>
    <WarningsAsErrors />
    <SourceAnalysisTreatErrorsAsWarnings>true</SourceAnalysisTreatErrorsAsWarnings>
    <StyleCopEnabled>false</StyleCopEnabled>
    <TargetFrameworkVersionString>70</TargetFrameworkVersionString>
  </PropertyGroup>

  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug70.NoXaml|AnyCPU' ">
    <TargetFrameworks>net7.0-windows</TargetFrameworks>
    <PlatformTarget>AnyCPU</PlatformTarget>
    <DebugSymbols>true</DebugSymbols>
    <DebugType>full</DebugType>
    <OutputPath>bin\$(Configuration)\</OutputPath>
    <DefineConstants>DEBUG;WPF;NETCORE;CODE_ANALYSIS;WPF45;WPF40;NOXAML</DefineConstants>
    <TreatWarningsAsErrors>false</TreatWarningsAsErrors>
    <WarningsAsErrors />
    <SourceAnalysisTreatErrorsAsWarnings>true</SourceAnalysisTreatErrorsAsWarnings>
    <StyleCopEnabled>false</StyleCopEnabled>
    <NoXaml>true</NoXaml>
    <GenerateImplicitStyles>true</GenerateImplicitStyles>
    <TargetFrameworkVersionString>70</TargetFrameworkVersionString>
  </PropertyGroup> 

The file can be found here: Telerik_UI_for_WPF_Source_[Version]\Build\Imports\NetCoreConfigurations.targets.