When a content control check box updates it state at run-time, any local formatting is lost.

Workaround: Formatting defined in style definition is properly kept.

Type a few lines in RadRichTextBox.
Double-clicking within a word, holding down the mouse button on the second click, and then drag it. 

Actual: Dragging will move the word instead of extending the selection as it should.
Expected: The selection should be extended. Moving the word shouldn't happen unless you release after the double click and then click and drag. 

The GetSupportedExtensions method of DocumentFormatProvidersManager throws NullReferenceException when invoked.

Workaround:

HashSet<string> supportedExtensions = new HashSet<string>();
foreach (var provider in DocumentFormatProvidersManager.FormatProviders)
{
    foreach (var extension in provider.SupportedExtensions)
    {
        supportedExtensions.Add(extension);
    }
}

Bookmarks are not imported and missing from a specific document scenario.

Workaround: Import and then export the document using the WordsProcessing library and then open it with the editor.

When inserting a content control (structured document tag) into an empty RadDocument using one of the overloads of the InsertStructuredDocumentTag method accessible from RadRichTextBox and RadDocumentEditor, a NullReferenceException is thrown.

Workaround: Invoke the EnsureDocumentMeasuredAndArranged method before inserting the content control:

document.EnsureDocumentMeasuredAndArranged();

RadDocumentEditor editor = new RadDocumentEditor(document);
editor.InsertStructuredDocumentTag(SdtType.CheckBox);

When the unit type is set to an inch:

Expected: to could be able to place the RulerThumb on every 1/16 of an inch.
Actual: be able to place the RulerThumb to every 1/8 of an inch.