Disabling fullscreen grays out maximize option

Upon turning on fullscreen (Options > Video Settings > Fullscreen: ON) and turning fullscreen back off, the maximize option became grayed out. In order to maximize the window I had to close Minecraft and re-open it.

Extra info that might matter: Minecraft was maximized when I turned on full screen.

I have reproduced this two times in a row, so repro shouldn't be too difficult.