being able to change mastery's/runes in practice tool

i think you should add a button to change mastery's in the practice tool without having to exit the game. i want to try different mastery's with champs but to do so i have to exit the game waste time by having to pick champ ect. load time ect. just to try a new mastery page. ok now here is a thought in pvp games sometime u have the wrong mastery page. you might think about giving until minions spawn or until you leave the summoners platform to change mastery page/runes. once minions spawn or leave summoner platform pages are locked in. this might be a good idea with the changes coming to the rift soon cause people might have the wrong page at the start of change.