Default Fullscreen app issue on Nexus 7 2013 LTE

Dear developers and friends, i just bought and rooted my nexus 7 2013 and it has been working flawlessly save for one. I read up on the fullscreen app which enables the tablet to utilise its total screen by hiding the statusbar and the navigation bar. It worked for me for a day and the next day ti said something stopped working and when i rebooted the device, i was not able to use the app anymore. I am still able to get the touch icons at the corners but they are unresponsive and basically not working, and not getting fullscreen anymore. I really enjoyed reading in fullscreen mode and switching swiftly back to the old mode whenever i could. I really miss it guys. Hope you all would have had a solution for me.