[TABLE="width: 500"]
<tbody>[TR]
[TD]Private Sub CommandButton1_MouseDown(ByVal Button As Integer, ByVal Shift As Integer, ByVal X As Single, ByVal Y As Single)
If Y < CommandButton1.Height / 2 Then
MsgBox "Call macro here"
Else
MsgBox "Display error message here"
End If
End Sub[/TD]
[/TR]
</tbody>[/TABLE]