I've had a lot of times when working on a photograph that the selection gets in the way. Usually it's when I'm zoomed way in and trying to look at something the moving selection line can be very distracting.
There's a simple solution to temporarily hide the moving selection without actually deleting it. To do this use Ctrl + H / Cmd + H. The selection line will be not be seen on the screen but it still works as a selection. To make the line visible use Ctrl + H / Cmd + H again.
This works great when you are trying to apply a slight color change and wanting to make sure the edges are changing cleanly.
In this example, hiding the edge would allow me to make sure a color change was working properly all the way to the edge of the shirt without the moving line getting in the way.
If you do hide the selection and get busy doing other things, it can be easy to forget there is still an active selection. You might start using another tool, and things won't work because you have a hidden selection. Just use the Ctrl + H / Cmd + H again to show your selection.
Hopefully you'll realize something has been selected before spending too much time scratching your head wondering why things aren't working at usual.