I used the ultra power saving mode,but it wont give me the simple home screen and it wont limit apps,but it limits the options on the system.And there is no "Turn off ultra power saving mode" button there
I also have the Ultra Power Saving Mode in my Samsung Galaxy Grand Prime.
This mode disable animations reduces display and closes all the background application and disable wifi etc. and do all the possible way to reduce battery by shutting down background tasks.
If you want to turn off this mode then drag your status bar/notification panel and click,"'Disable Ultra Power Saving Mode".
My hubby has the same problem firsr time he did this saving mode it had an option to turn it off now the second time it disappeared did you get it fixed?