The following example uses code including the CommandBarEvents property to support any code to handle a mouse click on a command bar.
Private WithEvents ce As CommandBarEvents
Sub Test()
Dim c As CommandBarControl
Set c = Application.VBE.CommandBars("Tools").Controls(1)
Set ce = Application.VBE.Events.CommandBarEvents(c)
End Sub
Private Sub ce_Click(ByVal CommandBarControl As Object, Handled As Boolean, CancelDefault As Boolean)
' Put event-handling code here
End Sub