I realized a set of two radiobuttons that should operate in a group, 
either one or the other but I cannot find the correct way to combine 
these two radio buttons although I can see the dialog in which they are 
used. only both buttons are on and clicking on them cannot set either of 
the off. I tried to find an example how to do this on internet.  I just 
send the used files along. Can anybody help me.