Unfortunately I don’t think the widget that is used allow this. One workaround is to export the matrice as a CSV file and open it in Excel.
I agree it would be nice, but it is actually not Capella-related. The right place to ask this question or request this feature would be the Sirius forum (
http://www.eclipse.org/forums/index.php?t=thread&frm_id=262).
Thank you Stephane. The export to CSV function is an useful turnaround indeed.