snapped windows don't come back to their original size

[Damien]

windows dragged to the sides of the screen can be "snapped", maximised to half the screen. If dragged again to the middle of the screen they get their initial size back.

However if a window is snapped and closed while snapped, it will retain the snap size and position (without being snapped) instead of opening with the original values.

to reproduce:
- open a non-maximised window, like files. Note the size and position.
- snap it to a side
- close it with the cross button
- open files again, note it now takes the size and position of a snapped window
- try to unsnap it by dragging, fail.
- manually resize to a more convenient size.

I noticed this bug working with two office documents side by side. I closed them after being done with them, but the next document I opened was in an incorrect, off-centered position instead of being in the middle of the screen.

applications should retain the snap status like it already retain size and position, and be able to get back to their previous size and position when unsnapped. That or the snap values shouldn't overwrite the original values and a new window should keep using the original values.