Addin.Visible = True | False
None.
Boolean. If True, the Addin object is visible. If False, the Addin object is not visible.
The default value of this property is determined within the addin. So, you should specifically set this property value when the addin is loaded.
Sub ToggleVisibility (nID)
'Called by Hide/Unhide Output Window menu item
If Not outputAddin Is Nothing Then
' Toggle Output Window visibility
If outputAddin.Visible Then
outputAddin.Visible = False
Else
outputAddin.Visible = True
End If
End If
End Sub