I found what caused the problem. I don't know why it did nor does Jim Slater after talking to him.

I had subclassed the standard combobox into 4 unique subclassed comboboxes. Each of the 4 had been set up with the controlsource referencing a table instead of a view of the table. Each combobox was place in a column of a grid replacing the normal textbox. The controlsource of the each combobox in the grid referenced the view of the table instead of the table.

As soon as I changed the controlsource of the unique subclassed combobox (parent of the combobox in the grid) to reference the view of the table the problem went away.

So apparently you cannot override the controlsource of a combobox.

Regards,

Bill