 <p>Why must RichTextBox be readonly? What happens if it is not readonly?</p> <p>If this is a known bug in the datdgrid then i would consider hacking a if-it-looks-right-it-is-right solution (i think this beats modifying/fixing a dll).</p> <p>Examples, does it must be a hyperlink? Can it be a textblock instead (which you'd handle the hyperlinking part in code)?</p>