Currently there is no way I know of to reset the sorting on a page after you sort via the little arrows or the keyboard shortcut Alt+F7.

This can be especially annoying when the default sorting field is not visible on the page, as there is no way to go back to that sorting.

Quick example, imagine a list page that is by default sorted by Line No. which is not visible on this page, now I sort by an imaginary column "Date", after I am done with that I'd like to be able to reset the sorting to the standard sorting of Line No. but there is currently no known way that I know of that doesn't require me to close and re-open the page.