First of all, please change your thread title, it has nothing to do with the subject.
About gravitybox, you have to activate it in xposed and reboot. Then, when you activate the navbar option, you have to reboot one more time for it to work.
Its work for me anyway let me check again..
Remove these Files in ur System/app
If it double means delete that also
Then flash the mod again..
I have delete the files as you said and flahs it and i...
Please , How you can Fix SU ? Where i can find the zip to flash ??? ANyone can help me ??