Using v115.7 in debian 12.

I prefer to open pdf files with the default viewer in the operating system, not on a firefox browser tab. I have gone into settings->general->applications and configured selected "Use system default application" for PDF files. If I click on a pdf file it downloads to my Downloads folder, which is the usual and preferred behaviour. If I click the downloaded files icon on firefox's toolbar, I see the file I downloaded, all good. If I open the folder with all downloaded files, and click on the file, it opens in the OS's default viewer, all good. On the other hand, if I click on the downloaded files icon on firefox's toolbar and simply select the downloaded file from the displayed list, it opens on a firefox browser tab. This is driving me bananas. How do I configure firefox to launch the default system application instead?