Thanks for your answers. I think, the 'class & event solution' is best.

Meanwhile I found these two sites:
http://www.vb-fun.de/cgi-bin/loadfra.../tip0178.shtml
http://www.jkp-ads.com/Articles/ControlHandler00.asp

I use the code of no. 1, as I found this link first. It's written in German but keywords like 'class', module, etc.' are so obvious, you should not encounter any language problem.

The second link is in English and the author offers a bunch of really, really good tools (and explanations).

Using two classes (one for check boxes and another for option buttons) I do not need a single 'Button_Click' procedure anymore. Saves plenty of time ...

NP