alt+tab with mate desktop

If I open firefox (1), I open firefox(2) again, and then I open audacious

Only with alt+tab, I can change between audacious and firefox(1) or (2)

In the pannel bar, If if click on firefox(1), firefox(2), audacious, and press alt+tab, audacious goes to the end of the list icons

I have tested with the latest marco version.

on audacious -> settings -> appearance -> interface plugin ->

with "GTK interface", alt+tab works

with "Winamp classic interface" <- here is the issue

I have tested with metacity and same problem

I have tested in lxde and it works

more info:

Audacious