Hi!

I've got a problem. I'm using an activex combobox in excel. It display 4 posible choices, and one of them is "Other". When someone select "other" there is a textbox named "tb" that should be filled. Otherwise tb should be invisible. Combobox change() function looks like that:

Public Sub ComboBox7_Change()
If IsNull(Sheet1.tb) Then
    'nothing'
Else
    If ComboBox7.ListIndex = 0 Then
        Sheet1.tb.Visible = True
    Else
        Sheet1.tb.Visible = False
    End If
End If

End Sub
Apears when I try to close excel - there is a question if I want to save changes and when I answers "Yes" it - somehow - call combobox7_change() function. In that moment textbox "tb" doesn'y exist, so there is an error message 

Compile error:

Method or data member not found
Could anyone help me, please? What I'm doing wrong?