> If I either a) click on the grid, or b) TAB to the grid, > listbox.click() > seems to fire, although the Trace window in the debugger indicates > that > NO code is executing. The event tracking output does not show > listbox.Click() firing. I would think that it's not code in the ListBox that's firing at all, rather it's code that may be buried somewhere in the Grid, possibly in the SetFocus method. I notice that the error relates to 'lcWhichText', which means the error could also be phrased as "Parameter Not Supplied", and this translates into: "I used to call this code from {here}, but then I changed something so I moved the call to {here} and added a PARAMETER. I may have forgotten to remove the old call." I'd load the form into the Class Browser, generate the text, then search for "ResetDispPay". When you've found all instances of it, put some ASSERTions or WAIT WINDOWs in the screen, and try again.