When I press the home button on my tablets why does it highlight an app?

[AC Question]

Every time i try to press the home button instead of taking me back to the homepage it just does nothing and highlights an app lets say for example contacts. PLEASE HELP SAMSUNG GALAXY TAB 3 LITE

 

[B. Diddy]

Welcome to Android Central! You might have TalkBack turned on. Go to Settings>Accessibility​ and see if anything there is turned on.

 

[AlphaTango414]

Try wiping system cache partition also.