I have a simple userform with a combox and two option buttons. I would
like to populate the combobox with a range if optionbutton1 is clicked
and with another range if ob2 is clicked. I keep getting a "Run time
error 13, type mismatch" message. My code is below.

Private Sub OptionButton1_Click()
UserForm1.ComboBox1.RowSource = Range("a1:a10")
End Sub

Can anyone tell me what is wrong with this? Looks legit to me.

Thanks for any help,
Greg