red border when open application/task manager

[raza07]

hello,
here the story when is get my tab it was working very slow and then i updated the software still was working slow but faster than before then strange thing happened the wall paper pixels were broken, and then i shut down the tab then open it again then the wallpaper was fixed again. now when i open task manager / pen memo etc the screen border become red and they blink and when swiping in some software if it hangs for a sec it blinks red from border and when checking options in developer options they screen turn purple for a sec and then again red borders. i didn't restore to factory settings yet but if there is any solution other than that it will be really help full

thanks