compatible problems with a plugin

Hallo Tomas,

I have a little problem but I don’t find a solution.
See on my site: https://www.hnbi.de

I put in sidebar a calender with a plugin it called “Quick event Manager”. But the calender is not displayed right. Same on the normal post side:

https://www.hnbi.de/hnbi/kalender/

Do you have an idea to solve the problem?

thanks in advanced
Jo