volkiller730: you are right, i had once a similar problem, since that time I put them in a separate sheet.
Rudi55: I checked and tried. My way doesn't change anything. I add also an separate variable (constant one) or change the text field. Nothing happened. It seems that all variable are lost. I'm sorry, but I didn't find a mistake.
The funny part: I add a new layout, just a blank one and changed if plane is destroyed go to the new layout and show variable. There it works. So the error is somewhere in the event restarts.