Inasmuch as, when using the Oxygen XSLT debugger, I often navigate straight to the files that I want to run or navigate to a line and set a breakpoint and then want to just run it, but I used to also often just rerun the previous set of files I’d been debugging because the debugger’s file selectors weren’t keeping up with my gyrations in the editor panels.
Enter the “Link with Editor” button. Clicking once on the 
button beside the file selectors once you’ve got the files that you want to run visible in the editor panels will update the selectors to reflect the currently selected panels. A useful button, indeed.
(You probably want to click it again straight away to turn the feature off again, just so the selections don’t change every time the debugger’s focus shifts to another file for a breakpoint or, rarity of rarities, an error.)