SUMMARY Firefox's Picture In Picture windows doesn't resize with their aspect ratio, which make large dark borders appear and isn't practical. STEPS TO REPRODUCE 1. Play a video from Firefox 2. Activate PIP mode 3. Resize the PIP Window OBSERVED RESULT Firefox's Picture In Picture windows doesn't resize with their aspect ratio, which make large dark borders appear and isn't practical. EXPECTED RESULT Firefox's Picture In Picture windows resize with their aspect ratio, as under Microsoft Windows. SOFTWARE/OS VERSIONS Linux/KDE Plasma: Neon 5.24.3 (available in About System) KDE Plasma Version: 5.24.3 KDE Frameworks Version: 5.91 Qt Version: 5.12.3
It sounds to me like upstream issue. You may need to report it in Firefox website.
Looping Nate for double checking.
I believe that is correct.