Menu: fix runtime warning

Menu.qml:292: TypeError: Cannot read property 'visible' of undefined

Change-Id: I95cebf3a45e4ef5d663e344a8d716a0a5810d0ad
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@digia.com>
Menu: Put popup mouse area over list view

Task-number: QTBUG-34034
Change-Id: Ie54e02e742cbc51ed65c53180741505e48faadca
Reviewed-by: Jens Bache-Wiig <jens.bache-wiig@digia.com>
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@digia.com>
Reviewed-by: Caroline Chao <caroline.chao@digia.com>