Did you google it? I've just googled

  how to get out of fullscreen mode in minecraft-pi

and got some possibilities suggested. One suggested ...

  F11 for Fullscreen

  By default, F11 (Fn + F11 on some keyboards) toggles fullscreen mode.

  If that doesn't help, pause the game (by pressing Esc) and go into
  Options# # Controls# and check your keybinding for toggling fullscreen
  mode (under the "Miscellaneous" section).

  Alternatively, you can go into Options# # Video Settings# and click
  "Fullscreen: ON" to turn it off manually.



On 2021-02-15, Olivier Morin  wrote:
> Hi, just got a raspberry pi with Minecraft-pi edition installed on it. I am
also trying to show my son how to program.
> We are REALLY stuck since Minecraft-pi starts and goes directly to fullscreen
mode without giving us a chance to move the window side-by-side with the python
editor/shell. We tried using two monitors, we tried Avery combination of keys.
We tried 
killing processes at the console...
>
> Any help would be greatly appreciated.
>
>
> On Wednesday, October 30, 2013 at 1:11:55 PM UTC-7, michael...@gmail.com
wrote:
>> On Friday, October 4, 2013 10:53:35 AM UTC-7, Michael Barlow wrote:
>> > On Friday, October 4, 2013 1:10:04 AM UTC-7, Justin C wrote:
>> >
>> > > On 2013-10-04, Michael Barlow  wrote:
>> >
>> > >
>> >
>> > > > I am trying to setup minecraft pi edition to teach programming to my
son. I have the model B pi setup with rasbian. However, when I run minecraft
the mouse keeps constantly jumping which causes the view to reorient. This
makes the game unusable. 
I have tried different power adaptors (thinking it might be usb power
dropping), I have tried different keyboards, mice, and monitors. I have tried
with minecraft maximized and in windowed modes. I have tried different
configurations of memory sharing 
and overclocking vs no overclocking. No luck. The mouse seems to operate fine
in x windows.
>> >
>> > >
>> >
>> > > >
>> >
>> > >
>> >
>> > > > Has anyone else experienced this issue? I have searched google,
raspberrypi.org, etc and can't find anyone experiencing the same issues. Next
steps are trying a complete SD card wipe, reinstall everything, and then buying
a replacement pi.
>> >
>> > >
>> >
>> > > >
>> >
>> > >
>> >
>> > > > thanks to anyone with ideas or info.
>> >
>> > >
>> >
>> > >
>> >
>> > >
>> >
>> > > Sounds like a mouse issue. Though I've never seen that with a
>> >
>> > >
>> >
>> > > USB mouse, only with a PS/2 mouse sometime around the transition
>> >
>> > >
>> >
>> > > from COM port mouses to PS/2 mouses. When I had that, whichever
>> >
>> > >
>> >
>> > > way I moved the mouse it always went down and left. IIRC the
>> >
>> > >
>> >
>> > > solution was in the configs somewhere. But... big but: The
>> >
>> > >
>> >
>> > > technology is well established now, and this shouldn't be the
>> >
>> > >
>> >
>> > > probelm you're seeing.
>> >
>> > >
>> >
>> > >
>> >
>> > >
>> >
>> > > Check the mouse with another computer to rule out a hardware
>> >
>> > >
>> >
>> > > problem.
>> >
>> > >
>> >
>> > >
>> >
>> > >
>> >
>> > > Justin.
>> >
>> > >
>> >
>> > >
>> >
>> > >
>> >
>> > > --
>> >
>> > >
>> >
>> > > Justin C, by the sea.
>> >
>> >
>> >
>> > Unfortunately, I have tried 3 different optical USB mice and the problem
still occurs.
>> Figured it out. The issue was the SD card. I reformatted the SD card and
installed Noobs/Raspbian. Now the mouse is working properly.

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