I assume you are talking about when the text in the cell is too long to be accomodated by the area of the button and so when you hover over the button a balloon comes up that shows the entire text in the cell.  You can turn off that balloon by setting the TipStyleCell property of the grid to "Hide".  You could do this in the InitializeLayout event handler like so: 

e.Layout.Override.TipStyleCell =

TipStyle.Hide;

I hope this helps.

Michael S.