This is what I have so far, from what I've gather from how others accomplished it.
Set iComboBoxes = New Collection
'Cycling through all controls and gathering all comboboxes
For Each CTRL In UserForm1.Controls
If TypeName(CTRL) = "ComboBox" Then
iComboBoxes.Add CTRL
'Setting onmousedown event handler
CTRL.OnMouseDown = "=AllComboBoxes_MouseDown(" & CTRL.Name & ")"
End If
Next CTRL
I get an error saying that the object doesn't support this property or method, on the line where I set the OnMouseDown event handler. I've seen other people do it like this, so I must be missing something.