portal layout removed column event

Hello!
I'm implementing a gui using a portal layout, allowing user to add and remove columns using default show column menus.
Is there a way to detect a column removal? Or, alternatively, is there a way to be notified that a portlet has been removed?
I could not find any suitable specific handler on javadocs.

Using Smartgwt 4.0p
SmartClient Version: v9.0p_2014-01-05/LGPL Development Only (built 2014-01-05)

Thanks in advance for the answer

UPDATE:
CloseClickHandler and VisibilityChangeHandler do not notify anything on column removal