The following applies to UFT in General, not necessarily with Win XP. The standard font used by UFT is an older version of MS Sans Serif. If another font, or perhaps a later Unicode version of the Sans Serif font has been substituted, Foxpro will enlarge the boxes to compensate. If the font selected is not available in an appropriate size, the boxes can enlarge.
Suggest that you check Win.ini to see if any fonts have been substituted for MS Sans Serif. Also check in Control Panel-Display Settings to see font sizes, font types, etc. for the Win XP Desktop settings. UFT uses the same font that is used globally for windows in versions prior to XP.