When creating a hyperlink from selected text using the InsertHyperinkDialog, trailing spaces shouldn't be included in the hyperlink, as in MS Word.

In MS Word, there is special command in Home -> Paragraph -> Borders dropdown -> Horizontal Line, which inserts special drawing similar to 3D horizontal line in a paragraph. Such line should be exported to <hr> tag during HTML export, and respectively <hr> tag should be imported as Horizontal Line.

Note: the representation of the horizontal line in the docx document is as follows: 

        <w:pict>
          <v:rect id="_x0000_i1027" style="width:0;height:1.5pt" o:hralign="center" o:hrstd="t" o:hr="t" fillcolor="#a0a0a0" stroked="f"/>
        </w:pict>

Workaround: 
Currently, you can add a horizontal line using a table with a single border. Here is some code demonstrating how to do this:

----------------------------------------------------------

var document = new RadDocument();
var editor = new RadDocumentEditor(document);

Table table = new Table();
var topBorder = new Telerik.Windows.Documents.Model.Border(1, BorderStyle.Single, Colors.Red);
var borders = new TableBorders(table.Borders.Left, topBorder, table.Borders.Right, table.Borders.Bottom);
table.Borders = borders;

var row = new TableRow();
var dummyCell = new TableCell();
var dummyParagraph = new Paragraph();
dummyParagraph.FontSize = 0;
dummyParagraph.LineSpacing = 0;
dummyParagraph.SpacingAfter = 0;
dummyParagraph.SpacingBefore = 0;
dummyCell.Blocks.Add(dummyParagraph);
row.Cells.Add(dummyCell);
table.Rows.Add(row);
			
editor.InsertTable(table, shouldInsertParagraphBeforeTable: true);            
this.radRichTextBox.Document = document;

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Add API for adding embedded file streams (a.k.a. file attachments) to the PDF file produced during the export to PDF.

Implement IF and ASK fields.

Currently PdfFormatProvider does not use the track-changes styles when exporting the document. So the different text color, underline, strike through or borders will not appear in the exported PDF.

There are cases when it is unwanted to be able to add words to a custom dictionary. In that case the DocumentSpellChecker should not create a custom dictionary in the IsolatedStorage and this should be reflected in the default UI: 
1. SpellCheckingDialog - the buttons "buttonAddToDictionary" and "buttonEditCustomDictionary". 
2. ContextMenu - the item "Add to dictionary". 

Create UI for editing CITATION fields, a.k.a. "citation placeholder", which later you can edit. 

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

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.

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.

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

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.

Implement child dialogs for Style Formatting Properties Dialog. This will allow users to modify Style's properties related to font properties, paragraph properties, tabs, numbering and borders.

DocxFormatProvider should support external content (altChunk (Anchor for Imported External Content)) when importing documents. The current version omits anything referred as external content. 

Note: exporting from Telerik Reporting to DOCX when the report contains HtmlTextBox will create such elements.

Currently UI code generated by RadRichTextBox wizard is not localized out of the box. Add support for easier localization.

Add support for optional (a.k.a. soft) hyphens. In MS Word, such are inserted using Ctrl + -. If the word need to be split as there is no enough space on the line, the word is split after the optional hyphen.

In Word, for paragraphs in a list: 

1. The bullet/number uses the value of the first line indent 

2.1 The text on the first line is aligned according to the left indent when the left indent is smaller than the first line indent (the usual case). 

2.2 If the first line indent is smaller than the left indent, the first line aligns with the rest of the text, using the value of the left indent property. 

2.3 When there are tab stops, they are used for the position of the text. In RadRichTextBox, the text in the first line always aligns according to the FirstLine indent. 

Also, tab stops can be used to position the text after the bullet/number.

The "em" unit will be particularly useful for setting the width of columns/the height of rows in tables.