3 listboxes one under another.

What do you mean by "one under another"? Do you mean that you only see one list box at a time and determine via code which list box should be visible, manipulating its visible property and calling its zOrder method?

If this is what you mean, I encountered something similar just yesterday. If this is not what you mean, I have never seen this problem. My problems went away as soon as I made all the list boxes visible.