I just noticed that the debugger also suffers from this problem. Doing a quick grep over the source reveals even more places that might cause problems (where only the bg or only the fg color is set).

I think in ScrolledList.py the background="white" should just be removed. This and setting the fg color to black when the bg color is set to yellow (Debugger.py) makes the debugger usable.

Checkboxes and radiobuttons seem to be messed up in general (forced white bg but using system fg color (white on white on my system); not idles but Tkinters or TKs fault).