Sorry, I forgot to include the edit mask that was giving me problems.
The edit mask I am using which is behaving strangely in an Edit is:
!999\-000\-0000;1;_

This mask works great in a grid--exactly the way you would think, based on
the behavior of TMaskEdit. But when used with a TIB_Edit, it doesn't
behave the way I expected it to--like TMaskEdit. The mask appears
correctly, but when you start typing, the cursor positions itself all the
way to the right (at the end of the mask display). As you continue typing,
the mask DOES enforce itself, but it fills strangely--the text appears to
"scroll" left, until you have completed the input.

Why doesn't it behave like TMaskEdit? In a TIB_Grid, it does.