Tim,
Why the VFP designers ever thought this was appropriate behavior I'll never know.
Put the code that Sergey posted in your lowest level Textbox class and every textbox will be fixed. Provided that you do have one textbox from which all others are derived. If you don't you should, you can fix all the oversights on the VFP controls in this way, like labels not being transparent and autosizing by default etc.
>If I hold the cursor at the end of the yyyy part and hold down the backspace
>then the cursor does not stop at the end of the field and continues to the
>next field and deletes its text as well.