Text editors

Hi guys,

I'm using TimyMCE in Moodle 2.7.2 and I have a problem with the tables.
When I add a table to my resource (mostly in quiz questions) everything works fine. But once I saved the question, I can't edit the numer of columns and rows of a table. The numbers in the "insert/edit table" box are grey and I can't change them.

What am I doing wrong? Is there a solution to that?

Thank you very much in advance!
Dominik