When exporting RadDocument to HTML comments are omitted. 

MS Word, for example, adds comments as end notes using JavaScript.

Form fields are the legacy way to insert an editable controls in a document (text boxes, checkboxes, dropdowns) by using the FORMTEXT, FORMCHECKBOX and FORMDROPDOWN fields.

This includes the legacy Frames (described in OOXML with 'framePr' element).

Do not confuse with content controls (structured document tags) (see http://feedback.telerik.com/Project/143/Feedback/Details/113730 ) and with ActiveX controls.

When an action is executed, say delete, and you perform undo, the text that is inserted back in the control is selected. In RadRichTextBox the end position of the selection is brought into view.

Add a way to convert between RadRichTextBox's RadDocument and RadWordsProcessing's RadFlowDocument. 

This will enable integration scenarios between the two products, including using RadWordsProcessing's format providers for import and export.

Add support for the following RTF tags (crop from top, bottom, left, right):

\picropt, \piccropb, \piccropl, \piccropr 

Consider raising an event when the images are finished loading, or an option for loading the images synchronously. 

Implement Mirror margins similar to the option in MS Word.

In MS Word, this is controlled using Page Setup dialog -> Margins -> Pages -> Multiple pages: -> Mirror margins. Another possible options are 2 pages per sheet and Book fold.

Add support for nested track changes revisions. Currently, when a user tries to delete text added by another user, RadRichTextBox simply removes it and does not mark it as a change.

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.

When FlowDirection is set to RightToLeft:

<telerik:RadRichTextBox FlowDirection="RightToLeft" />

RadRichTextBox could work as system's RichTextBox - to layout the text correctly and swap the vertical scrollbar on the left side. Another option to consider is to change the default paragraph style (or 'Normal' style?) to have RTL flow.

Currently, when this property is set, the text gets reversed and the vertical scrollbar stays on the right side.

There is already Author property but it is not filled automatically. It should be filled using the RequestCurrentUserInfo event of the RadDocument, which is currently only used for track changes revisions. 

Currently saving to an .rtf document with footnotes strips the footnotes and endnotes.

Add a property that can control whether a table row is allowed to break across pages or not.

When the content of an entire row is copied and the caret is inserted in the left most column of a row, then the content of each cell in that row should be overwritten with the contents in the clipboard when pasted.

When such content is pasted just after a table, new row is added and filled with values.

When such content is pasted in paragraph, new table is created.

Expose TableOfContentsField.TabStopLeader property which will allow changing the leaders of the tab stops used within the field result. Currently such property exists, but it's internal.

Docx format can encode symbol characters using the <sym> element. Currently this concept is not supported in the document model, and the element is converted to normal character on import. Add support for similar element in the document model, and for its export to Docx.

The background-color attribute could be used for setting a background.

When an IncludePictureField is selected, the ImageMiniToolBar should be shown.

When HTML is imported it may contain invalid images. In such case show the alternative text if there is such text.

Add support for TIME field. More information here:
https://support.office.com/en-us/article/Field-codes-Time-field-6cb8fcef-310a-4646-ae6b-886d88335c90?ui=en-US&rs=en-US&ad=US