Click the "Display" Button on Game panel ,Then the Menu can't stop showing when hit Key"Space"

Hi, My Unity version is 5.3.1 ,here is my problem:

when I click the Dispaly button, the display menu show up naturally. However, if I press "Space" Key then ( in game panel), the menu just show up again, which means I can't let the game receive the "Space" Key ... Forgive my poor English , but I really need help...