VS 2005 Add Combobox1 To A Form?

[Code]...

1. Add Combobox1 to a form and add the above code

2. Run the form

3. Enter some text not in the drop down list or leave the combobox text blank

4. Click the form close button ( the "X" )

5. The error will be displayed, "ERROR - Invalid Entry!"

6. Press OK on the messagebox

This is where something goes wrong. If you click the Dropdown arrow of the combobox, the dropdown list wont stay open. ( unless you hold the mouse button down ). This doesn't happen if you click or tab to another control (like a text box). Then after the messagebox is displayed the ComboBox still works fine.