You can drag and drop but it's a bit picky - grab the file tab and drop it in the other pane's tabstrip. Definitely something that could be improved (as well a

You can drag and drop but it's a bit picky - grab the file tab and drop it in the other pane's tabstrip. Definitely something that could be improved (as well as splitting to two panes gives you 2 panes of the same file..)