I think it was Jim Booth who used to say this in his sessions. It's a valuable lesson one shouldn't forget. Given that frmDialog.SCX is a form with just one label and the following code in the Init:
Thisform.lblMsg.Caption = m.tcText
DO FORM frmDialog.SCX WITH "Deleting customer."
DELETE NEXT 1
Well, I didn't at first glance when I reviewed the code. However, displaying a form makes an awful lot of events happen, like the Activate event. Obviously (after thinking about it, of course), any of these events can change the current work area and not properly reset it. DELETE doesn't necessarily delete the customer record; it can be any record in any table. In fact, destructive commands like DELETE, ZAP or even REPLACE should never be used without the IN clause.