Chris,

I see that you are not bound to anything in the sample code. Some controls behave differently when they are not bound to anything. I tried binding to thisform.Tag and to a c(254) field too in my replication of the problem, which leads to the questions I asked.

How big is the real field that you want to try and bind the cbo to? Why are you using a cbo and not a textbox? cbo is most often bound to a simple integer field that is a foreign key into a lookup table.

>It's not bound to anything on the sample form. But we have tried it bound to a cursor with fields 254 characters wide. In all situations it does the same thing.
>
>On the sample form all I did was drag the cbo from the toolbox onto the form and then run the form. The problem happens straight away.