>Has anyone encountered problems when setting the cursor position inside an edit box after set the value of the edit box. (The edit box is read only, in a grid, and its controlsource is an expression)

I don't know about you, but when I set the cursor (actually, caret) position within an edit box using the SelStart property, I get no problems. I guess your problem stems from the fact that its ControlSource is an expression. VFP might be recalculating the contents of the control and resetting the caret position.

Have you tried using a memory variable to hold the edit box value instead?