Everything KDE from git master on top of openSUSE Tumbleweed, using the Plasma Wayland session STEPS TO REPRODUCE 1. Open Firefox and navigate to a page with a UI element that can accept image drags, such as the Pull/Merge Request submission page in GitLab or GitHub 1. Take a screenshot with Spectacle 2. Drag the screenshot from Spectacle's main window into the drop area in Firefox OBSERVED RESULT The cursor shows a "no drops allowed" shape and the image is not uploaded EXPECTED RESULT The cursor shows a "drops are accepted" shape and the image gets uploaded ADDITIONAL INFORMATION If I save the image from Spectacle on disk, and them drag it from Dolphin, the drag is accepted (though the cursor shape is still wrong, which is probably a separate bug). So it seems that something about the way Spectacle is formatting the drag data is causing the problem, because it works from Dolphin.
I'm unable to reproduce with Firefox 93 (tested on Xwayland and Wayland) on neon unstable.
Same, seems to be working now. Thanks for following up!