Currently, the only customization that can be performed is using HyperlinkToolTipFormatString property of RadRichTextBox, which sets the format for all hyperlinks in the document of the control. It would be nice if it were possible to be able to set different tooltips. 

Bold/Italic does not work for some font styles.

This might be a framework limitation in WPF: https://www.telerik.com/forums/some-fonts-are-not-able-to-bold-italic

Sample fonts list:

1. Tw Cen MT Condensed Extra Bold (bold/italic)
   
2. Tw Cen MT Condensed (bold/italic)
   
3. Sitka Text Semibold (italic)
   
4. Sitka Subheading Semibold (italic)
   
5. Sitka Small Semibold (italic)
   
6. Sitka Heading Semibold (italic)
   
7. Sitka Display Semibold (italic)
   
8. Sitka Banner Semibold (italic)
   
9. Segoe UI Variable Text Semibold (italic)
   
10. Segoe UI Variable Text Light (bold/italic)
    
11. Segoe UI Variable Display Light (bold/italic)
    
12. Segoe UI Semilight (bold/italic)
    
13. Segoe UI Semibold (bold/italic)
    
14. Segoe UI Light (bold/italic)
    
15. Segoe UI Black (italic)
    
16. Script MT Bold (bold/italic)
    
17. Rockwell Condensed (bold/italic)
    
18. Rockwell Extra Bold (italic)
    
19. Rage Italic (bold/italic)
    
20. OCR A Extended (bold/italic)
    
21. Nirmala UI Semilight (bold/italic)
    
22. Microsoft YaHei UI Light (bold/italic)
    
23. Microsoft YaHei Light (bold/italic)
    
24. Microsoft JhengHei UI Light (bold/italic)
    
25. Microsoft JhengHei Light (bold/italic)
    
26. Malgun Gothic Semilight (bold/italic)
    
27. Leelawadee UI Semilight (bold/italic)
    
28. Gloucester MT Extra Condensed (bold/italic)
    
29. Gill Sans Ultra Bold Condensed (bold/italic)
    
30. Gill Sans Ultra Bold (bold/italic)
    
31. Gill Sans MT Ext Condensed Bold (bold/italic)
    
32. Gill Sans MT Condensed (bold/italic)
    
33. Franklin Gothic Medium Cond (bold/italic)
    
34. Franklin Gothic Heavy (bold/italic)
    
35. Franklin Gothic Medium (bold/italic)
    
36. Franklin Gothic Demi (bold/italic)
    
37. Franklin Gothic Demi Cond (bold/italic)
    
38. Franklin Gothic Book (bold/italic)
    
39. Dubai Medium (bold/italic)
    
40. Dubai Light (bold/italic)
    
41. Corbel Light (bold/italic)
    
42. Copperplate Gothic Light (bold/italic)
    
43. Copperplate Gothic Bold (bold/italic)
    
44. Cooper Black (bold/italic)
    
45. Cascadia Mono SemiLight (bold/italic)
    
46. Cascadia Mono SemiBold (italic)
    
47. Cascadia Mono Light (bold/italic)
    
48. Cascadia Code SemiLight (bold/italic)
    
49. Cascadia Mono ExtraLight (bold/italic)
    
50. Cascadia Code SemiBold (italic)
    
51. Cascadia Code Light (bold/italic)
    
52. Cascadia Code ExtraLight (bold/italic)
    
53. Candara Light (bold/italic)
    
54. Calibri Light (bold/italic)
    
55. Britannic Bold (bold/italic)
    
56. Bodoni MT Condensed (bold/italic)
    
57. Bodoni MT Black (italic)
    
58. Bernard MT Condensed (bold/italic)
    
59. Bahnschrift SemiLight Condensed (bold/italic)
    
60. Bahnschrift SemiLight SemiConde (bold/italic)
    
61. Bahnschrift SemiLight (bold/italic)
    
62. Bahnschrift SemiBold (bold/italic)
    
63. Bahnschrift SemiBold SemiConden (bold/italic)
    
64. Bahnschrift SemiCondensed (bold/italic)
    
65. Bahnschrift SemiBold Condensed (bold/italic)
    
66. Bahnschrift Light Condensed (bold/italic)
    
67. Bahnschrift Light  (bold/italic)
    
68. Bahnschrift Condensed (bold/italic)
    
69. Arial Rounded MT Bold (bold/italic)
    
70. Arial Narrow (bold/italic)
    
71. Arial Black (italic)

Document exported to DOCX with 2025 Q2 cannot be opened by 2025 Q1 or previous versions.

Workaround: Use document processing to fix the document.

var processing_provider = new Telerik.Windows.Documents.Flow.FormatProviders.Docx.DocxFormatProvider();

var document = processing_provider.Import(File.ReadAllBytes("C:\\Users\\test\\Downloads\\word1.docx"),null);
var bytes_ = processing_provider.Export(document, null);

var rtb_provider = new Telerik.Windows.Documents.FormatProviders.OpenXml.Docx.DocxFormatProvider();
var doc = rtb_provider.Import(bytes_);
radRichTextBox.Document = doc;

Can be reproduced in the demo:

• Open the default document in the radrichtextbox demo
• Activate change tracking (button "Track Changes")
• Make a modification to the document (delete a paragraph)
• Hover your mouse over the delete text: the date in the revision info. has always ":00" for the seconds

In our processes, it is very important to know if a change happened before or after another action. If all the revisions have zero seconds, it's impossible to determine the order of the changes when they happened in the same minute.

This is not a new bug introduce in SP2: it was there in SP1.

The operating system region and language needs to be set to Japanese.

RichTextBox seems to have several issues with Japanese, but being locked from visibility or edit is the biggest one.

To recreate, start typing in Japanese, push the "right" arrow after selecting the IME option desired, then hit "spacebar." This seems to duplicate the text, then when trying to continue to type into the text field the text is no longer visible (yet the IME does display).

The native WPF RichTextBox has no issues (and also supports partial selection, etc.).

I've attached a video to show the behavior with 2025 Q1 telerik.

*note:* This is on a machine with NVIDIA graphics. I mention this as there may be some issues with RichTextBox and the hardware... When I'm in a virtual machine with a completely Japanese environment and virtual graphics driver, there is NO text visible at all when trying to type into the RichTextBox. Works fine with other controls and wpf RichTextBox.

This causes some problems if the hyperlink is edited and the document is exported and imported again.
Workaround:
private void RadRichTextBox1_DocumentChanged(object sender, EventArgs e)
{
    var document = radRichTextEditor1.Document;

    var fields = document.EnumerateChildrenOfType<FieldRangeStart>();

    foreach (FieldRangeStart item in fields)
    {
        radRichTextEditor1.DeleteAnnotationRange(item);
    }
}

When a new line is placed right after a nbsp, the new line is ignored in the layout. This can be reproduced by importing the following HTML:

First&nbsp;<br/>Second

Type in Japanese text in RichTextBox that word wraps beyond the first line and export it to PDF. The text should always be left aligned (as visually shown when typing) but has an "indent" when exported when the font is Segoe UI.

NullReferenceException is thrown when the document gets updated after TableRow objects were removed with the Remove method of the parent Rows collection of the Table.

The table.Rows.Remove method is not properly removing some of the rows.

Stacktrace:

Telerik.Windows.Documents.dll!Telerik.Windows.Documents.Model.TableGridMeasurer.CalculateTableCellMinMaxWidths(Telerik.Windows.Documents.Model.TableCell cell, float availableWidth) Line 137 C#  Telerik.Windows.Documents.dll!Telerik.Windows.Documents.Model.TableGridMeasurer.CalculateTableMinMaxWidths(Telerik.Windows.Documents.Model.Table table, float availableWidth) Line 165 C#  Telerik.Windows.Documents.dll!Telerik.Windows.Documents.Model.TableGridMeasurer.MeasureAutoFit(Telerik.Windows.Documents.Model.Table table, float availableWidth) Line 229 C#
  Telerik.Windows.Documents.dll!Telerik.Windows.Documents.Model.Table.RecalculateColumnWidths(float measureWidth) Line 1151 C#
  Telerik.Windows.Documents.dll!Telerik.Windows.Documents.Model.Table.RecalculateTableGrid(float measureWidth) Line 1249 C#  Telerik.Windows.Documents.dll!Telerik.Windows.Documents.Layout.TableLayoutBox.MeasureOverride(Telerik.Windows.Documents.Model.SizeF availableSize) Line 265 C#  Telerik.Windows.Documents.dll!Telerik.Windows.Documents.Layout.LayoutElement.MeasureCore(Telerik.Windows.Documents.Model.SizeF availableSize) Line 933 C#  Telerik.Windows.Documents.dll!Telerik.Windows.Documents.Layout.LayoutElement.Measure(Telerik.Windows.Documents.Model.SizeF availableSize) Line 836 C#  Telerik.Windows.Documents.dll!Telerik.Windows.Documents.Layout.SectionLayoutBox.MeasureOverrideInternal(Telerik.Windows.Documents.Model.SizeF availableSize) Line 721 C#  Telerik.Windows.Documents.dll!Telerik.Windows.Documents.Layout.SectionLayoutBox.MeasureOverride(Telerik.Windows.Documents.Model.SizeF availableSize) Line 468 C#  Telerik.Windows.Documents.dll!Telerik.Windows.Documents.Layout.LayoutElement.MeasureCore(Telerik.Windows.Documents.Model.SizeF availableSize) Line 933 C#  Telerik.Windows.Documents.dll!Telerik.Windows.Documents.Layout.LayoutElement.Measure(Telerik.Windows.Documents.Model.SizeF availableSize) Line 836 C#  Telerik.Windows.Documents.dll!Telerik.Windows.Documents.Layout.DocumentLayoutBox.MeasureOverrideInternal(Telerik.Windows.Documents.Model.SizeF availableSize) Line 223 C#  Telerik.Windows.Documents.dll!Telerik.Windows.Documents.Layout.DocumentLayoutBox.MeasureOverride(Telerik.Windows.Documents.Model.SizeF availableSize) Line 150 C#  Telerik.Windows.Documents.dll!Telerik.Windows.Documents.Layout.LayoutElement.MeasureCore(Telerik.Windows.Documents.Model.SizeF availableSize) Line 933 C#  Telerik.Windows.Documents.dll!Telerik.Windows.Documents.Layout.LayoutElement.Measure(Telerik.Windows.Documents.Model.SizeF availableSize) Line 836 C#  Telerik.Windows.Documents.dll!Telerik.Windows.Documents.Model.RadDocument.Measure(Telerik.Windows.Documents.Model.SizeF measureSize) Line 1515 C#  Telerik.Windows.Documents.dll!Telerik.Windows.Documents.UI.DocumentPrintLayoutPresenter.MeasureOverride(System.Windows.Size availableSize) Line 714 C#

To work this around, use the DeleteTableRow method of the RadDocumentEditor.

RadDocumentEditor documentEditor = new RadDocumentEditor(document);
documentEditor.DeleteTableRow(row);