While CyanogenMod is generally regarded as the biggest and best of the innumerable custom ROMs, some of the others tend to implement interesting additions to Android much sooner. The latest nightly builds of CM 11 (Android 4.4) have added something that's not exactly new, but should be very much appreciated by immigrants from other ROMs. Users can now long-press the physical or virtual Recents button to quickly open the last app "under" the current one. Observe:
GIF credit: Wesley J. Marcolino
It's a cool little touch akin to a quick tap of Alt-Tab in Windows. We're actually not sure which competing ROM implemented this first, but in a recent Reddit thread, users of Omni, Carbon, Paranoid Android, and others claim that it's been in their ROMs for a while. There's also a setting in the popular Xposed module GravityBox (very much recommended for root users who can't find a good non-stock ROM) for this behavior. The CyanogenMod changelog says that the addition was placed into nightly builds last week by Roman Birg, a Cyanogen Inc. employee who's also worked on the popular AOKP family of ROMs.
Wherever the new feature comes from, it's yet another little flourish that should please power users. The long-press Recents switch will probably be implemented in the M10 snapshot release in early September, or the next month at the latest.