When you are near the bottom of a listbox and items are removed, a blank gap appears.
I created this demo to illustrate the effect.
Compiled with WinFBE 2.2.0 32-bit.
ListBoxGapExample.bas
Thanks I will check it out. I remember a similar report of this several years ago. The ListBox is ownerdrawn so maybe after the items are removed there needs to be a repaint or refresh called.