Hi Steve,
There are 2 things you can do. One is to add "-regress_fout no" to afni_proc.py, so all of the F-stats are not output. They are not so necessary anyway.
But the more simple thing to do it with the afni GUI. When choosing "OLay" or "Thr" volumes, put your mouse over the text to the left of the button (e.g. put the mouse cursor directly over 'OLay') and right-click. That should give a scrollable menu that is much easier to deal with.
- rick