The Docm (docx) and RTF files are not imported correctly. 

- Paragraph's alignment is not imported when RTF file is opened by RadRichTextBox
- Importing of Docm (docx) file does not imports images and does not apply correct borders of table

The equation objects in word document are not copied and imported correctly in RadRichTextBox

Invisible borders in html format are imported as black borders in RadRichTextBox

Resolution: 
This issue is addressed in the new version of the control - RadRichTextEditor. Please use the new control instead the RadRichTextBox. 

To reproduce, add a theme in design time and open the ThemeName drop down from the editor's SmartTag

To reproduce: create a Word document with a table. Design a more complex table with nested tables in each cell. Specify "None" border for the internal tables. When loading the document in the RadRichTextBox, the borders are displayed.

If you export a document using the HtmlFormatProvider, all style properties which contain measurement units are exported in pixel units. This makes the exported documents look much smaller when opened on devices with higher pixel density.

WORKAROUND: use Regex to find, convert and replace the font-size attributes

            HtmlFormatProvider html = new HtmlFormatProvider();
            string res = html.Export(document);
            Regex regex = new Regex(@"font-size: [0-9]*\.?[0-9]*px");
            Match match = null;

            do
            {
                match = regex.Match(res);
                if (!match.Success)
                {
                    break;
                }

                string value = match.Value.Substring("font-size: ".Length, match.Value.Length - "font-size: ".Length - "px".Length);
                double pts = double.Parse(value) * 72 / 96;
                res = res.Replace(match.Value, @"font-size: " + Math.Round(pts, 4) + "pt");
            } while (match.Success);

            File.WriteAllText("output.html", res);

To reproduce:

Open TelerikEditor and underline the whole text. Go to the end of a line and hold space. You will notice that the empty spaces are being underlined. The behavior is not the same as in Word.

Workaround:

Remove the underlining of the empty spaces at the end of the lines:

void Button_Click(object sender, EventArgs e)
{
    var caret = this.richTextBox.Document.CaretPosition;
    var originalPosition = new DocumentPosition(caret);
    caret.MoveToFirstPositionInDocument();
    do
    {
        caret.MoveToCurrentLineEnd();
        var endPos = new DocumentPosition(caret);

        caret.MoveToCurrentWordStart();
        caret.MoveToCurrentWordEnd();

        var startPos = new DocumentPosition(caret);

        this.richTextBox.Document.Selection.AddSelectionStart(startPos);
        this.richTextBox.Document.Selection.AddSelectionEnd(endPos);
        this.richTextBox.ChangeUnderlineDecoration(UnderlineType.None);
        this.richTextBox.Document.Selection.Clear();

        caret.MoveToCurrentLineEnd();

    }
    while (caret.MoveToNext());

    caret.MoveToPosition(originalPosition);
}

Beware that this workaround will not work in all cases. It should be used only prior to exporting or similar cases

Steps:
1) Launch The RichTextEditor
2) Clear all the existing content
3) Type some text for ex: zzzz
4) Select the whole text and try to hit the backspace 
5) The typed text is not cleared and even you keep hitting the backspace the text is not cleared sometimes, it just stays

Steps:
1) Launch the RichTextEditor
2) Clear the existing contents or open a new file (using File-> New)
3) Insert a table of any dimensions for ex: 2x2
4) Delete the above added table
5) Now try to insert a new table of any dimensions (For ex: 2x2)
6) You will get the following exception when you run the project using vs2010
Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index
7) In the demo application , you will see a Form1 error pop up opens up and makes the RichTextEditor completely blank

Can't see undo and redo button on the editor.

When you open the color dialog, "Add custom color", "Ok" and "Cancel" buttons are not completely visible. Currently the dialog box can't be re-sized making it hard for the user to use as the button names are not visible so the user can't be sure what is being clicked. See the attached fig.

As shown in the attached screen shot when as spell checking dialog is opened , "Close button is not seen on the form even though it is present. Spell checking dialog box needs to be re sized.

Launch the RichTextEditor and observe the button are not completely visible and some/ most of the dialog boxes cannot be re sized.
--> Home Tab
1) Find/ Replace dialog box, button overlap the textboxes behind them
2) Change Styles , this dialog box cannot be re sized currently 

-->Insert Tab
1) Hyperlink dialog box, this dialog box cannot be re sized currently 
2) BookMarks dialog box, this dialog box cannot be re sized currently
3) Cross Reference dialog box, this dialog box cannot be re sized currently
4) Format Code block Dialog box, this dialog box cannot be re sized currently
5) Insert Symbol dialog box, this dialog box cannot be re sized currently

--> References tab
1) Manage Sources 
2) Insert Caption
3) Cross reference

--> Review tab
1) Spell check dialog box
2) Protect document

Launch the RichTextEditor
1) Click the find and replace button on the ribbon bar
2) Close the find and replace dialog box
3) click the find/replace button again , the form doesn't open up

1) Run the RichTextEditor
2) As you can see there are already some images inserted in the document
3) Right click on any image , and click Edit Image, Image editor dialog box does open up. (as shown in the attached pic EditImageActive1.jpg)
4) click outside the image and right click on the image again, and this time you can see the Edit image option is disabled and this happens consistently. (as shown in the attached pic EditImageInactive.jpg)

One more thing to observe was upon right clicking the image sometimes the Edit image option does show up in the context menu and a different menu appears (as shown in the attached pic NoEditImageOption1)

Run the RadRichTextEditor
Right click on any image -> Text Wrapping -> More layout options (as shown in the attached fig MoreLayoutOptions.jpg)
Observe that the more layout options doesn't show up most of the times.

1) Launch the RadRichTextEditor
2) Create  a new file
3) go to insert tab and hit "Header" icon (Header & Footer section)
4) Notice the caret blinks on the top left corner of the document
5) Enter some text for ex: zzzz and notice text entered doesn't show up
5) At this point when you double click outside the header section the whole header and footer section is lost
6) Now double click on the header section again even though the header section is not visible. Still the entered text is not displayed and notice the cursor blinks at the top left corner of the header section
7) Press enter key, now the entered text is displayed. 

1) Launch the RadRichTextEditor
2) enter some text (at least three lines)
3) select the whole content and apply bullets/ numbers 
5) Since the whole content is already selected, open the font color dialog box and try to apply a color (say red color)
6) Notice for the last item in the list , the selected color is not applied to the bullets/ numbers as shown in the attached figs