Why does a thick line appear when I press the home button or the power button?

[AC Question]

a thick line appears when i press the home button or the power button

i saw a line appeared on the screen on the rightside of the password bar. it happend after updating my device s4 GT-19500.... that line just pops-up when i press the home button or the power button

 

[BioFanatic]

Re: a thick line appears when i press the home button or the power button

Did you post the same question multiple times?