Every time I click the + button to expand the Minecraft window for the first time since the Login the screen with the actual game is still small and went to the bottom-left corner, and the rest of the screen is black. If I click the + again the window will become small again and again the window becomes normal Full Screen. This isn't a critical bug but it's quite annoying.

Step 1: Logs into Minecraft.
Step 2: Selects a Single Player Map and loads it.
Step 3: Clicks + button like on any Mac window to expand it.

What should have happened:
The Minecraft window should have covered the whole screen with the actual game the size of the window when i clicked the + button on the window.

What actually happened:
The window expanded but the actual game didn't and moved to the bottom left of the screen.

Note: this only happens the first time you load a Singe Player map since Login and doesn't always happen. (roughly 2 out of 5 times it does this). Happens a lot more often if you click the + while its loading the map.

You can fix this on your own by clicking again twice the + button on screen, but could you fix this?

(I couldn't find a bug already reported exactly like this one, if it's a duplicate I'm really sorry for wasting your time)