Option Explicit
Private Sub CheckBox1_Click()
With ComboBox1
'If CheckBox1 Then .ColumnWidths = "20;20" Else .ColumnWidths = "0;0"
If CheckBox1 Then .ColumnCount = 2 Else .ColumnCount = 0
End With
End Sub
Private Sub UserForm_Initialize()
With ComboBox1
.ColumnCount = 2
.ColumnWidths = "20;20"
.List = Range("A1:B10").Value
End With
CheckBox1.Value = True
End Sub