Default [Q] bottom right docked app keeps disappearing

Hi, i have only noticed since i updated to 4.4.2 that the icon on the right hand side on docked apps randomly disappear. I doubt it is because of 4.4.2 because i saw a thread that someone had this issue on another phone but there was no solution posted, but has anyone got an idea to fix this?

here is a picture of it to better explain maybe?