+1  A: 

C-x 0 did the trick

Oleg Tarasenko
+12  A: 

If i understand you correctly you want to C-x 0 in the window you want to close.

johanbev
... in the *window* you want to close to be precise.
Eisen
I edited the post to say that. Best to use the correct terminology rather than the incorrect terminology :)
jrockway
talking of correct terminology, shouldn't be 'in the buffer you want to close'? oh, and +1 for the answer.
Ashwin
Nopes, should be window (using emacs' own terms), at least thats what describe key says. Cheers.
johanbev
+3  A: 

The interactive solution is to put the cursor in the bottom buffer and hit C-x 0.

mobrule
+2  A: 

Hi,

the other option if you enjoy using the mouse is to right click on the modeline of the buffer you want to close (the one which shows helpers.py in your screenshot). The only thing which you have to note is that you should not click on the file name, as right click on file name is bind to switch buffer by default.

danielpoe
Cool, I didn't know that
justinhj
WOW!!! Really interesting. Didn't know about this
Oleg Tarasenko