Bug 2183356

Recently - I think since the flatpaks were rebuilt on the F38 runtime - we're seeing a failure of the openQA Evince test on Silverblue (but not Workstation, where we use RPM-packaged Evince of course):

https://openqa.fedoraproject.org/tests/1861635#step/save_as/11

what's going on, best I can tell, is this.

What the test is trying to do is check that "Save As" behaves as intended. The test runs Evince from the overview (so it opens with no document loaded and an "Open..." button visible). It clicks the Open... button, navigates to the user's Documents folder, and opens a PDF that's there (we set that up earlier in the test). Then, it opens the burger menu, clicks "Save As...", types a new file name, and hits the Save button. It expects this to result in the newly-named file being saved in the same directory as the original file (Documents). On the RPM-packaged Evince, and previously with the Flatpak evince, this is what happened. Now, however, with the Flatpak evince, "Save As..." actually saves the file to a different folder entirely: it winds up in something like `/run/user/1000/doc/d3d864ff` (I'm guessing the final element is a random string).

Of course, we can tweak the test to switch to the Documents folder before saving. But it does seem like a wrong behaviour. I'm not sure if it can be fixed?

I've reproduced this manually, too. Notably, it does *not* happen if, instead of using Evince's own "Open..." button to open the file, I open it by going to the Documents folder in Nautilus and double-clicking the PDF file. On *that* path, when I hit "Save As...", the correct Documents folder is pre-selected as the save target.