Holding down space or tab freezes the client and game

Whenever i hold tab to look at the items of team and enemies my game freezes i can't move my mouse or do anything, same when i hold space (which i sometimes do because i dont play with locked screen). Occasionally bugging my game and making me exit and black screen for several seconds. Suggestions? edit: also, after games end there's no client for me to go to. i have to force close everytime and restart league. i should mention during game as well i can't alttab out and pull up the league client (where you can see "game in progress")