This is a strange one. We've set up a POS, and every now and then it is suddenly impossible to enter anything in the item lookup code field of the pos, or scan an item. You can type anything you want, nothing will appear. I can solve this by logging in as administrator, go into security mode, press Ctrl+S, select the item lookup code column, close the "Security" window (nothing checked there, btw), Ctrl+S again, leave security mode. After that all is normal, for a while. Has anyone seen this before?