Left swipe and window tiling

Whenever I swipe in from the left of the screen in Windows 8.1, the programs I have open - usually only Outlook and Chrome - sit side-by-side, each taking up half of the screen.

That's ok, but when I close one of them by dragging the divider to the right or just closing it normally, the remaining program does not resize to its previous setting and stays at the split screen 50% size.

Is there any way around this, as it's very annoying.

Thanks