Made a clean install of 14.04 beta2 (4cf9e5ef2c1c362317c90312c76cfda0 *ubuntu-14.04-beta2-desktop-i386.iso), installed gnome-panel package and launched GNOME session FlashBack (Compiz) - there is not application switcher on <Alt>+<Tab>.
Made a clean install of 14.04 beta2 (4cf9e5ef2c1c36 2317c90312c76cf da0 *ubuntu- 14.04-beta2- desktop- i386.iso) ,
installed gnome-panel package and launched GNOME session FlashBack (Compiz) - there is not application switcher on <Alt>+<Tab>.