>I tried that, it does the same thing, the cursor is moved to the beginning of the box and not where it's being set the line before. I have stepped through it and the SELSTART is getting set correctly, but the RETURN .F. or RETURN 0 seems to reset that.

I just created a test form from the form base class and the textbox base class.
I entered return 0 in the valid event of the textbox and then added another textbox to the tab order. After entering some characters and pressing return, the cursor remains at the end of the text I entered and the focus remains as well. I get the same behavior from an editbox.

Unless, escape is pressed, in which case the cursor jumps to the beginning of the text if the control is bound to data. Otherwise the text is removed as if backspace were pressed through the entire string.

I typically use keypress for stuff like this.