SUMMARY
Tags are difficult to use! There are several problems.

1. Creating a new tag from the tags dialog on a person's contact dialog. After creating the tag and returning to the list of tags, the newly created tag is not present. The dialog must be closed and re-opened to be used.

2. After creating a new tag, it is not present in the dropdown list of tags available from the tag text box above the list of contacts. Kontact must be closed and re-opened for the tag to be used.

3. It is difficult to use tags as a filter. On first use, every tag is set in the dropdown from the tag text box above the list of contacts. Selecting just one requires clicking every other one to unselect them. 
Although "All" is the initial state, there is no single click way to re-generate it, nor to "clear all".


SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: Fedora 30
(available in About System)
KDE Plasma Version: 5.15.5
KDE Frameworks Version: 5.59.0
Qt Version: 5.12.4

ADDITIONAL INFORMATION