How to un-split or merge a split editor window?

[CodeSandwich]

I've split the editor window horizotally:

How do I undo this operation? I want to have a single editor tab again like this:

I closed the tab and opened the file again to achieve this, but there must be a better way. I haven't found any button or a menu option to do that. I tried dragging the barrier to shrink one of them to zero, but that didn't actually un-split the editor.

[breiler]

It should work fine to just drag it to zero again:

Screencast.from.2025-01-08.20-11-14.mp4

[CodeSandwich]

It does, I tried it again and it just worked, I don't why it didn't previously. Thank you for the quick answer!