Show Master Compatibility view suddenly different

Hi, not sure what I did, but suddenly I only see the lines of the “Show Master Compatibility” view, and not the shape of the letters. I tried to restart and switching it on and off, but no luck. Any suggestions?

Can you show a screenshot?

Of course @GeorgSeifert , thanks for looking into it.

Never mind, I figured it out: turning the heatmap plugin off and on again fixed the issue.