Please tell us some basic information before asking for help: Model Name: Zen6 Firmware Version:132
It is possible for me to long-swipe up on the recent "button" (not really a button) to activate multi-window mode (this setting is oddly found under settings --> advanced --> screenshot). It doesn't seem possible to customize the back "button" to do anything on long-swipe up, unless I'm missing it. The device does respond with an extra vibration when making the movement, though, so it does recognize the movement. I would love to be able to customize it to swap to the previously opened app as I did with FNG (now partially broken by Google) on A10. Just an idea. Same would be nice to be able to customize for long-swipe up on home, too. If not, FNG side gestures still work.