Disable Quick Play being used multiple times

My suggestion is simple and useful (I guess). So, we all know the Quick Play menu from the launcher under the play button. I suggest that when you use it(like when you press on a server) the button should be disabled until you close Minecraft. Why is this helpful? I have ''Multiple Instances'' turned off, but when you press that button multiple times, it starts multiple LabyMod instances. I tested that, and now my PC is saying its last prayers.