Hi Buried Alive,
Your solution sounded great. Tried it now, however it did not work.
Hi Takayuki Miyoshi,
I am afraid to switch back to the default theme and maybe have to fix my settins once I put on my current Theme again. I will write the support of my theme and ask if there is a clash with this particular plusing.
Thank you both for your answers. I fully appreciate it. If anyone else has got any good ideas, you are welcome to share them.
Lisa