The custom document properties enable the users to define their own properties to the document or use one of the predefined. 

In most of the cases, the document variables can be used instead. More information about them you can find at http://docs.telerik.com/devtools/document-processing/libraries/radwordsprocessing/concepts/fields/document-variables

Add support for import and export of floating tables.

Add support for the background tag: html - CSS color vs. background-color vs. background? - Stack Overflow

The background property might contain an actual image (it is not locked to color values).

When exporting, an option of how to create the PDF bookmarks should be provided:
- Using the RadFlowDocument bookmarks
- Using document Headings

Office Open XML defines a mechanism for the storage of content which is not defined by this Office Open XML Standard, for example extensions developed by future software applications.

The stored data could be an image.

Exception when there are merge fields in the header/footer and one performs mail merge: 

Unable to cast object of type 'Telerik.Windows.Documents.Flow.Model.Header' to type 'Telerik.Windows.Documents.Flow.Model.BlockBase

The attached sample project below demonstrates a possible workaround for PAGE and NUMPAGES fields when exporting to PDF. The demo shows how to generate document from scratch containing PAGE and NUMPAGES fields and export it to PDF.

Find and Replace document elements with special characters.

• ^p - Paragraph Mark
• ^t - Tab Character
• ^? - Any Character
• ^# - Any Digit
• ^$ - Any Letter
• ^^ - Caret Character
• ^u - Section Character
• ^v - Paragraph Character
• ^c - Clipboard Contents
• ^n - Column Break
• ^+ - Em Dash
• ^= - En Dash
• ^e - Endnote Mark
• ^d - Field
• ^& - Find What Text
• ^f - Footnote Mark
• ^g - Graphic
• ^l - Manual Line Break
• ^m - Manual Page Break
• ^~ - Nonbreaking Hyphen
• ^s - Nonbreaking Space
• ^- - Optional Hyphen
• ^b - Section Break
• ^w - White Space

When inserting a section between two paragraphs the section parent is not correct.

Example:

Paragraph paragraph1 = editor.InsertParagraph();
Paragraph paragraph2 = editor.InsertParagraph();
editor.InsertSection();
Paragraph paragraph3 = editor.InsertParagraph();

Expected:

paragraph1.Parent == paragraph2.Parent
paragraph2.Parent  != paragraph3.Parent 

Actual:

paragraph1.Parent != paragraph2.Parent
paragraph2.Parent  == paragraph3.Parent