Is there a way to close all the splits except the current one?
Update:
I use the filemanager plugin. When I open a file with it, I get three splits, where the opened file is in the middle. On the left side I have the file manager, while on the right side I have an empty split.
I came up with this quick fix. It's not a general solution, but when I open just one file with the file manager, it does the job:
"Alt-q": "command:tree,NextSplit,Quit"