SUMMARY
Thanks for finally rolling out the latest version of Okular to ubuntu/snap. Unfortunately, right now the options "Open new files in tabs" and "Switch to existing tab if file is already open" are disregarded. When launching Okular from the console, the following error message is printed:
```Qt: Session management error: Could not open network socket```
and
```qt.xkb.compose: failed to create compose table```

The --unique flag does not change the result.

STEPS TO REPRODUCE
1. sudo snap install okular
2. okular file.pdf
3. okular otherfile.pdf
4. okular file.pdf

OBSERVED RESULT
Three Okular windows with file.pdf open twice

EXPECTED RESULT
One Okular window with two tabs

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Ubuntu 20.04
(available in About System)
Qt Version: 5.12.8

ADDITIONAL INFORMATION
Before the recent update, tabs used to work (but the "Switch to existing tab if file is already open" option did not exist).