Quickly after Facebook's Chathead announcement, Paranoid Android released their HALO popup notification manager app which took the mod scene by storm! You can now use this revolutionary feature without having to sacrifice your favorite Rom. Developer "zst123" has developed an Xposed module that uses Xposed Framework to bring HALO to your device no matter what Rom you are running. This should work perfectly on any device that is running ICS or newer. It should be noted that this is not the complete version of Halo, rather it is only the popup window part of halo that allows you to multitask. Check out the source link below for more info.