Default Keyboard and ui buttons occasionaly crashing

Hey guys ive got this problem where my keyboard sometimes crashes and when i click on text input box the keyboard doesnt pop up. The ui buttons(back,home, multitasking) also half crash as when i am on a app sometimes when i click back it doesnt go bsck and sometimes it does work. Am i alone on this bug or does anyone else have this problem

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XPERIA ARC S- ICS 4.0.4 Offical ~~~DoomKernel ICS v5~~~~~Original Xperia S ROM V1.0 with xperia s lockscreen. mostly running touchwiz 5.0 or xperia s ics home