I use side by side editing often.
It was a hassle opening the file, then clicking on the tab to open to the right.
I found an easier shortcut to open the file in split view from the quick open (⌘P) file list.
- Quick open (⌘P) file list.
- Highlight the file and press Control + Enter (⌃Enter)
- The file will open to the side.
By the way, I'm using macOS.