ListBox extension (grey checks)

UPDATE(2003-12-06): Off-by-one error when using large font sizes fixed. _________________________________________________ This is a class that extends standard VB.ListBox control when its style is set to 1 - Checkbox. In addition to the standard checked/unchecked states listbox items can be marked as unknown (greyed) too. Also, mouse clicks/dbl-clicks anywhere on the item are interpreted as selection requests. This behaviour closely emulates the listbox control implementation in the Outlook Categories dialog. Enjoy!