Game can be opened twice and then close both versions (full repro known)

So I found this bug when while playing, I noticed I was getting abominable fps. After alt-tabbing out to check if I had anything open that would be causing this, I noticed that I had a second version of League open (the game itself, not the client). Curious, I opened the second one to discover that it was actually the ending screen from my last game. I pressed the "continue" button, as it was clearly the cause of my low fps, only to find that it closed both of league games open, the finished one and the one I was in.

What I theorized had happened (and later confirmed on customs) was that I had alt-tabbed out of the game on the end screen (instead of clicking continue), then had started a new game in the client. Thus I had two open games. It also appears that clicking continue sends a message to the client to close league windows, rather than closing it directly, and thus closes all open league windows.

(Note that this was done on OSX) Steps:

1. Start a game
2. Win or Los
3. Do not click continue
4. Alt-tab to the client
5. You should be able to start a new game, do that
6. Once the game finishes loading fully, alt-tab to the old game
7. Click continue
8. Both game applications will close

Solutions:

• Make the league games operate on a singleton pattern (the client already does this)
• Make leaving the after-game review close all open games
• Make it so that clicking continue only closes the game in which continue was clicked

That's all!