SUMMARY STEPS TO REPRODUCE 1. File→Open 2. It does nothing OBSERVED RESULT Nothing doesn't make. Any dialog window with files. EXPECTED RESULT This open the dialog window for choice file to be open. SOFTWARE/OS VERSIONS Windows: macOS: Linux/KDE Plasma: elementary os with LXDE and Xanmod Kernel 5.6.12 (available in About System) KDE Plasma Version: KDE Frameworks Version: 5.68.0 Qt Version: 5.14.1 ADDITIONAL INFORMATION Okular snap Ubuntu package.
Same observation here, with the latest snap available in ubuntu 20.04. It's not limited to "open", but also - more importantly - to "save as".