In some complex script languages, like Telugu and Thai language, some characters are grouped (e.g. consonants + vowels) in new grapheme. 

For example, type 'p' in Telugu - 'జ', followed by 'ో' - they are combined in new grapheme - 'జో', or paste the following Thai grapheme: ชื

UI correctly visualizes this, but:
- Text measuring assumes that the grapheme width is equal to the sum of the widths of its parts (characters), which is not correct. Selection and caret position are scrambled because of this.
- There are document positions between  the grapheme parts (characters), but shouldn't.
- When the caret is before the grapheme, deleting with "Delete" key deletes the grapheme in multiple steps (character by character), but should delete it in single step. Deleting with "Backspace" works correctly.
- There are some unsupported combinations in some languages. For example in Thai, typing 'z' then 'y' will produce grapheme, but typing 'w' then 'y' will not produce grapheme, and the 'y' should be ignored.

KeyNotFoundException is thrown when loading a document with a custom bibliographic style applied.

As a workaround, you can change the current bibliographic style to one of the predefined styles before the export of the document.

...
this.radRichTextBox.CommandExecuting += RadRichTextBox_CommandExecuting;
...

...
private void RadRichTextBox_CommandExecuting(object sender, CommandExecutingEventArgs e)
{
    if (e.Command is SaveCommand)
    {
        this.radRichTextBox.ChangeBibliographicStyle(new APAFifthEditionStyle());
    }
}

Korean language input does not work correctly on Windows 11 versions after 22H2 (OS Build 22621.1265).

This is related to an update to the Microsoft Input Method Editor (IME). The workaround is to enable the "Previous version of Microsoft IME" (check the attached screenshots for the steps).

Implement import of bullets and numbering which use the old Word 6.0/Word 95 format from RTF. This includes, but is not limited to, the following RTF tags: \pnlvlN, \pnlvlblt, \pnlvlbody, \pnlvlcont. See RTF specification, "Word 6.0 and Word 95 RTF" heading for full description.

WordPad and some legacy systems export lists with this formatting, so the construction is relatively widespread.

According to the specification, if RTF reader doesn't support specific bullets/numbering tags, it can use the \pntext tag to read the bullets/numbering as plain text; but currently RadRichTextBox always ignores the \pntext tag. Because of this, the bullets or numbers of lists in the old format are missing after import.

When text is using fonts with defined ligatures (e.g. Calibri, Gabriola, etc.) and contains character groups with defined ligature for it, the text width is measured incorrectly (shorter that it should be). As caret and selection navigates on positions computed by this measuring system, they are not synchronized with what is shown in the UI (which correctly respects the ligatures), and there is slight offset from the real character positions and/or clipping of part of the letters at the end of the line.

Examples of such groups are (depending on the font) "tt", "ff", "ffi".

Importing a document with block-level content controls from XAML causes them to become corrupt. If you scroll to a position in which the said control is only partially visible a NullReferenceException is thrown.

A possible workaround would be to initially save the document as a DOCX (just exporting it to DOCX will not fix the issue as the information is already corrupt).

Another way to reproduce this issue:

1. Create a new document and insert a Rich Text Content Control.

2. Save the document as a XAML file.

3. Reopen the XAML file.

4. Move the caret inside the Content Control.

5. Try to insert a new line by hitting Enter - no new line is added as the content control is marked as Inline Level after the import in step 3.

Case 2: 

Create a document with TOC where the content control of the TOC contains some other inlines.