To reproduce:

1. Insert content spanning 3 pages
2. Ensure a single page is visualized in the viewport 
3. Start selecting from the beginning of the content till the end by dragging the mouse
4. Press Delete

The issue is a regression introduced in R3 2021 SP1.

When importing a XAML document that contains a Content control with PrefixMappings to its TextProperties` DataBinding an exception is thrown: 'Telerik.Windows.Documents.Model.StructuredDocumentTags.DataBinding.PrefixMappings' threw an exception.'

The issue is observed when the added table is preceded by a paragraph with a font size different from the default one. As the issue is caused by a broken mouse capture, the following workaround can be employed:

someRandomFrameworkElement.CaptureMouse();

someRandomFrameworkElement.ReleaseMouseCapture();

When a whole paragraph is selected and the Set Numbering Value command is executed, the numbering value of the next paragraph is changed instead of the current one.

private void radRichTextBox_CommandExecuting(object sender, CommandExecutingEventArgs e)
{
    if (e.Command is ShowSetNumberingValueDialogCommand)
    {
        this.radRichTextBox.Document.CaretPosition.MoveToPosition(this.radRichTextBox.Document.Selection.Ranges.First.StartPosition);
    }
}

Using the microsoft word,In docx document,inserting a shape,and add the text context to the shape,then save.

when radrichtextbox  open the file,the program crashed.

Exception when importing a document with an empty table.

Workaround: Remove the empty tables:

DocxFormatProvider provider = new DocxFormatProvider();
var doc = provider.Import(File.ReadAllBytes(@"C:\Users\mpc\Downloads\22-51.docx"));

foreach (var section in doc.Sections)
{
    var tables = section.EnumerateChildrenOfType<Table>();
    foreach (var table in tables.ToList())
    {
        if (table.Rows.Count == 0)
        {
            section.Blocks.Remove(table);
        }
    }
}
radRichTextBox.Document = doc;

1. In MS Word, create a table with text in every cell, but just before the table, add a paragraph with text (you cannot reproduce the problem with an empty paragraph)
2. In the RadRichTextBox, create a new document
3. Activate Review/Track Changes
4. Copy and paste all the content from MS Word >> as a result none of the cells in the table has change tracking markup
5. If you copy only the table from MS Word (without the non-empty paragraph), it is working as expected

Having two mention providers and using the second right after using the first one actually loads the source of the first provider.