Using VFP 3 to do a Point of Sale System

where the item code is entered in a text box and in the valid method i add the item direct into the table.
and call
thisform.grid1.refresh

the grid's control source is the table field

enter one or two items the grid refreshes ok, but if you place a third item it doesn't show.

i have to click on the grid for it to refresh. this is probably a bug.

Anyone experienced this? Tried to solve using set focus on the valid method - which incidentally doesn't work.