Champ Select, Mastery Change Screen Unclosable [NEW CLIENT]

I was in Champ Select Changing some Masteries around and got trapped there due to the close button not working on the Mastery Screen so I could not select my champ... I had created a new page on the mastery screen so I thought that was the main culprit for the bug. I am running the new client and had previously recreated the bug (just the once), but now can no longer recreate it, I believe it may be a one time per Champ Select Screen thing because the first time I had encountered it I was on in Ranked Solo/Duo Champ Select Screen and the first time I recreated it I was in Custom Champ Select Screen.

The way I recreated it originally was entering in to Champ Select, entering mastery change screen creating a new mastery page, select a few masteries and attempt to exit the trap I got myself into. If someone could re-create this it would be greatly appreciated.

-Frostirian