Created attachment 122229 [details]
Disabled filter dialog

SUMMARY


STEPS TO REPRODUCE
1. In Kontact To-do view there is a menu entry View->Filter. When clicking on Filter, there is one entry with a radio button saying "No filter".
2. Selecting "Settings->Manage View Filters..." it open a modal dialog where everything except the Search field is disabled, and where there are no filters.

OBSERVED RESULT
As above

EXPECTED RESULT
You should get a dialog, where you can add/delete/modify filters

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 
KDE Plasma Version: 5.16.4
KDE Frameworks Version: 5.61.0
Qt Version: 5.12.2

ADDITIONAL INFORMATION
This is a new installation, but I kept my /home partition. I did - to the best of my ability - clean up everything pertaining to Akonadi, as I had had to give up to Thunderbird for a couple of years. And besides these minor annoyances so far I'm glad to be back :)