So since today I’ve been having this bug where everytime I play a game my ROBLOX client is in fullscreen when I never touched the settings. When I turn Fullscreen off in settings and try to play another game, the client is in fullscreen again…
I’ve noticed some other people on twitter tweeting about it as well… Is this a new update or just a bug? lol
I’ve been getting reports of this in my game as well.
Oh I noticed this too. I keep having to hit F11 every time I enter a game. Even if it is just a single tap… It annoys me far more than it should 
Maybe ROBLOX is trying to make ppl play in full screen like AAA games do 
I hope not, I have to disable fullscreen in every game I buy because I don’t like using fullscreen with more than 1 monitor.
I think this is unintentional. Can you navigate to AppData\Local\Roblox and look for a file named GlobalBasicSettings_[Number] and check what the value of the fullscreen tag is?
It should look like: <bool name="Fullscreen">false</bool>
Is the value true? If it’s true try changing it to false and see if that resolves the issue.
This resolves the issue for me.
It’s already set to false, but still fullscreens when I join certain games…
It’s still happening 3 days later, I’ve noticed even more reports
We know what the issue is and it should be fixed pretty soon. Hopefully next release. Basically whenever you open studio, it accidentally sets your fullscreen setting to true.
Still getting this…
And sometimes the client makes itself the top screen permanently so you have to minimize the client to see your windows behind it. Anyone else get this too?
I did what TG101 said and turned it to false, and that fixed the problem, but we shouldn’t have to do that.