Some odd behavior not present in 5.2. Not overly serious, but still "feels" odd...
1) browse implementors of #at:
2) with hand in upper pane, click select + drag downward, the hand into the lower pane
3) if traceMessages is on, notice the text selection in the lower pane!
4) with traceMessages off, instead of text selection, it does nothing, but when red button is released, the list continued to scroll "invisibly".