I recently upgraded to a bigger monitor and find myself using the window splitter quite often - but I noticed that there is still room for optimization:
When I have 1 file open, I often want to see a referenced class/file - I use F2 and it opens in another Tab.
But quite often I want to see them side by side!
The only current option is to use "Split Vertically" and then - in the new splitter - use F2, which just takes too long!
A better option would be a shortcut (e.g. SHIFT+F2) to open a file directly in a new splitter - very similar to a browser's "Open in new Window/Tab".
This would really make my life easier.