Hello pjo,
Yes. Hints "pop-up" when a display field is too short to display all the information in a field (such as a name in a grid), whenever the cursor is over the field. This occurs even if the form opens "under" the current cursor position, and so usually appears as "random" behaviour to a user.
Check the Service Pack page to make sure that the last Service Pack (PTF) for 6.8A in installed, or, upgrade to the current release of Payables - there were lots of useful improvements.