[Plib-devel] [PATCH] puListBox.cxx: don't crash with empty list + setTopItem(0)

[Melchior F. <mf...@us...>]

The attached patch makes sure that plib doesn't crash if a puListBox
was created with an empty list and the top item is set to 0 (which
happens on "up" arrow in puList, for example). In this case

    else if ( top > num-1 )

evaluates to (0 > -1) -> true, which sets 

       top = num-1;   -> -1

which accesses invalid memory with list[-1] in puListBox.cxx:135.

m.