[OS X TeX] funny behaviour of texshop help window

[Doris Wagner]

hi list,

on my mac, when I open texshop help and apply cmd+ (for a larger  
font), the help window displays in a larger font as wanted; but when I  
apply cmd- for decreasing the font again, nothing happens (if there is  
no other window open) or the font of the preview or editor becomes  
smaller;

in addition, if I change from TeXShop to another application, the  
TeXShop Help Window remains in front of (that is: still overlaps) the  
window of the other app.

???
can anyone explain to me this funny behaviour?

tia
doris