@Daniel Mosquin, is that something to report to xenForo? I can't do new postings there. But first, why aren't all Mac users affected? Surely all our users aren't using PCs.
OK my bad, I tried the same test on a mac and it can see both files. There is no file filter in play as there was on firefox/linux. Using chrome on the mac. What's more, it also works with chrome on linux. I do get a message with all the lower case file types, but the actual browse window then works correctly. So I guess it is only Firefox that doesn't work right. Honestly Firefox now doesn't work right with many web sites, so I guess this is a non-starter. I'll switch to using the forums with chrome, and see how that works. Thanks for all the time investigating, Wendy. -E
I doubt it: 50.1.0. I think the current Linux Firefox is around 53. Actually the distro I'm running in different locations, OpenSuse 13.1, has been end-of-lifed, I'm in the process of doing full OS upgrades. Which is a tremendous PITA!
Hopefully a last note on this. Running Firefox 53.0.2 (under Linux Mint 18.1) I experienced the same problem with the upload menu as shown in the screen shot. It works fine under the Chromium Browser, so I will use Chromium for these forums. Further I now think the drag-n-drop problem is specific to the KDE plasma desktop. Mint has a more recent version than I was using, and now I can see that the drag-n-drop cursor icon sometimes goes to an 'x' while in the drop window. When this happens the drop fails. I believe in the previous version the cursor change simple wasn't being shown. The only config I haven't looked at is Firefox/Mac.
Thanks for the explanation, @emery (and I'm so glad you figured it out). By same problem, you mean this one where it only displays files with a lower case extension? Please correct me if I'm wrong.