A "FontSize" setting cannot be applied to multiple paragraphs when the font size of the character at the beginning of selection is equal to the value which is going to be set.
Update: the issue is duplicate of http://feedback.telerik.com/Project/143/Feedback/Details/173836 .
The fix will be included in 2016 Q1.

After you have inserted a new row from the context menu of the RadRichTextBox, it becomes selected and then if you want to add a new row from the context menu again, the option is disabled. 

You should be able to add a new row, so the insert command must be enabled.

Introduce support for import/export of form feed character ( "\f")

- There should be a formatting symbol for the character

- Pressing Ctrl+Shift+Space should insert the character (standard MS Word shortcut)

- Import from docx should be implemented

- The symbol should be treated as a separator between words when spell-checking

When Charformat is used as a general switch the formatting of the first letter of the field name is applied to the whole result.

Also, consider implementing \*MERGEFORMAT - This switch applies the formatting of the previous result to the new result. For example, if you select the name displayed by the field { AUTHOR \* MERGEFORMAT } and apply bold formatting, Word retains the bold formatting when the field is updated to display a new author name.

In MergeFields the general switch may be used to format the Result Text. The text may appear in lowercase, uppercase, title case and so on.

When paragraph is in list, the user can choose "Set Numbering Value" which will change the appropriate level Starting Index and will create a new list (or continue the previous one).

The display mode of all fields is changed to Code, so that the export could work correctly and nested fields would be persisted.
Consider optimizing the algorithm, so that fields take less time to be exported.

Add support for comparing documents.

Popups (ImageMiniToolBar and SelectionMiniToolBar) stay on most top (act as if "Always on Top" is set to them) even if they had lost focus. 

Workaround: Attach to LostFocus or LostKeyboardFocus events and hide the toolbar in the handler:
this.radRichTextBox.LostFocus += (sender, e) =>
{
    this.radRichTextBox.SelectionMiniToolBar.Hide();
    this.radRichTextBox.ImageMiniToolBar.Hide();
};

When cells with borders are copied from Microsoft Excel and pasted in RadRichTextBox, some of the borders are missing depending on their type - for example double borders, but also some other types.

Steps to reproduce:
1. Type a long word in the editor. The word must be longer than the width of the page.
2. Set a hanging indent different than the default one.
3. Select part of the word starting from the beginning of the paragraph.
4. Add an annotation range, e.g. a Comment

Result: The hanging indent is not properly reflected in the editor.

The time it takes to apply highlighting to a document in Flow layout mode is more than expected. See ticket 555863 for a sample project and document.

When the tabbed document becomes a dockable window the ContextMenu Icons are no longer visible.

<telerik:RadDocking x:Name="radDocking"> 
 <telerik:RadDocking.DocumentHost> 
  <telerik:RadSplitContainer> 
   <telerik:RadPaneGroup> 
    <telerik:RadDocumentPane Title="Test"> 
     <telerik:RadRichTextBox x:Name="radRichTextBox" /> 
    </telerik:RadDocumentPane> 
   </telerik:RadPaneGroup> 
  </telerik:RadSplitContainer> 
 </telerik:RadDocking.DocumentHost> 
</telerik:RadDocking>

                 

Add adorners for selecting table rows, table columns and table cells with single click, similar to the ones in MS Word

In Word, default tab stops are not present in Paragraph's hanging indent. This leads to difference in the length of the Tab symbol in Word and RadRichTextBox, in cases when hanging is bigger than the default tab stop width.

Currently, when a page break is added to the document, the paragraph is not split in two. 
It will be better to split the paragraph and add one additional paragraph in order to achieve a more consistent look of the document when applying a style, adding one of the paragraphs to a list or having different first line/hanging indentation of the paragraphs.

DeleteTableRowCommand and DeleteTableColumnCommand should be able to delete all selected table rows/columns at once. Currently, the command cannot be executed when there is selection and  the user should delete the rows/columns one by one.

Japanese users use distributed text alignment, which justifies all lines including the last one.