The Upgrade Wizard for WPF cannot upgrade projects targeting the 4.8 .NET Framework.

1. Install the latest extension for WPF 
2. Create a new project targeting the 4.8 .NET Framework
3. Try to launch the Upgrade Wizard from the Telerik menu 
4. See the error - The project cannot be upgraded because the target framework does not match

The AM/PM value is not shown in the cell when formatting a time value.

Steps to reproduce:
1. Insert some time in a cell in spreadsheet (22:20)
2. Apply it a custom format that contains AM/PM (e.g. "h:mm AM/PM")

Observed: The AM/PM format is missing
Expected: AM or PM should be shown after the time (image attached) 

Declined: The changes could be applied if the user presses OK button instead of pressing Enter key. A new feedback item is open where the issue is described: https://feedback.telerik.com/Project/143/Feedback/Details/212042-spreadsheet-custom-number-type-values-in-format-cells-dialog-are-not-applied-wh

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.

Workaround: Import the document without using the default command

OpenFileDialog openFileDialog = new OpenFileDialog();
openFileDialog.Filter = "All Spreadsheet Files (*.txt, *.csv, *.pdf, *.xlsx)|*.txt;*.csv;*.pdf;*.xlsx|Excel Workbook (*.xlsx)|*.xlsx|CSV (Comma delimited) (*.csv)|*.csv|Text (Tab delimited) (*.txt)|*.txt|All Files (*.*)|*.*";
if (openFileDialog.ShowDialog() == true)
{
    string extension = Path.GetExtension(openFileDialog.SafeFileName);
    using (Stream input = openFileDialog.OpenFile())
    {
        Workbook workbook = WorkbookFormatProvidersManager.Import(extension, input);
        workbook.Name = openFileDialog.SafeFileName; // in the default implementation this is set after applying the document to RadSpreadsheet and triggers the event
       
        this.radSpreadsheet.Workbook = workbook;
    }
}

When using RadChat control and running the application, 2 binding errors appear in the Output Tab of Visual Studio.

System.Windows.Data Error: 4 : Cannot find source for binding with reference 'RelativeSource FindAncestor, AncestorType='Telerik.Windows.Controls.RadPromptInput', AncestorLevel='1''. BindingExpression:Path=Padding; DataItem=null; target element is 'RadGlyph' (Name=''); target property is 'Margin' (type 'Thickness')

System.Windows.Data Error: 4 : Cannot find source for binding with reference 'RelativeSource FindAncestor, AncestorType='Telerik.Windows.Controls.RadPromptInput', AncestorLevel='1''. BindingExpression:Path=Padding; DataItem=null; target element is 'RadGlyph' (Name=''); target property is 'Margin' (type 'Thickness')

Environment:

• Visual Studio 2026 Version 18.6.1 (May 2026 release)
• Visual Studio language: Japanese
• .NET 10 WPF project
• Telerik UI for WPF 2026.2.520
  

Problem:

Visual Studio freezes frequently while editing XAML when using Telerik UI for WPF 2026.2.520.
The issue does NOT occur with Telerik UI for WPF 2026.1.415.

Steps to reproduce:

1. Install the "Progress Telerik UI for WPF Extension"
2. Create a new WPF project using the Telerik extension/template (Empty)
3. Open the automatically generated MainWindow.xaml
4. Inside the existing <Grid> element, type:
   <Grid
5. At the moment XAML IntelliSense/code completion is triggered, Visual Studio freezes

Additional information:

• XAML Designer is disabled
• Deleting the .vs folder does not help
• No third-party Visual Studio extensions are installed
• The issue only occurs with Telerik UI for WPF 2026.2.520
• Downgrading to Telerik UI for WPF 2026.1.415 resolves the issue completely
  

Could you please confirm whether this is a known issue related to Visual Studio 2026 / .NET 10 compatibility?

Steps to reproduce: 

1. Enter in a cell =Today()
2. Show Format Cells dialog and set Custom format "d"

Expected: The value is the day of the month.
Actual: The date is formatted as short date but has to be day of the month.

Currently, the InputBoxText property of the RadChat control has a read-only purpose. It is updated only when you update the text via the UI. However, the property has also a public setter which implies that it can be set, but this doesn't work. 
Allow setting the InputBoxText property, which should update the text in the input TextBox.

For the moment, you can get the RadWatermarkTextBox element using the FindChildByType<T> method and set its Text property manually.

var textBox = this.chat.FindChildByType<RadWatermarkTextBox>();
textBox.SetCurrentValue(RadWatermarkTextBox.TextProperty, "new text")

As a result, the glyphs are not measured and positioned properly. The issue applies to the TrueType and Type1 fonts.