It sounds to me like you have more than one instance of the form with the combo box.

The code example you posted showed that you were declaring a new instance of the form, and yet you say the form was already opened. The new instance would be shown if you do a frm.showdialog where I suggested in the last message. If you do this I suspect you will see another form displayed with the combo with all the values.

However without seeing code it's difficult to guess exactly what you are trying to do.