3 Bugs/virus in my Samsung galaxy tab

What I Expected was,
That signs would actually work on android and other bugs were fix, but there is still bugs(i really don't know if it's a bug)in my android galaxy tab.

What actually happened was....
1.When i put signs in creative mod, it will just Lag, and then it will say that "Minecraft-Pocket Edition has Crashed".
2.In Survival Mode, when i planted a seed next to a planted seed, the other seed will be gone, and the one i put, also disappeared.
3.When in survival mode, i cant exit the game and go to another world, it will completely Crash and totally lag.

Steps to Reproduce:
1.I think signs would not work in Samsung galaxy tab (maybe others worked), so PLEASE fixed it, i really loved putting signs in minecraft PE
2.Please fix the Crash things and lag things, maybe my android will get virus.

I have last request:Bucket,Sun,Any New Blocks, Biome selector when creating a world, Please add also flatland,and ANYTHING to make Minecraft PE like Minecraft PC version