We're moving towards a tags-based system

As it seems I can not set the absinthe tag in the following thread:

During typing I do not get completion for absinthe but on each step I get a red background telling me I can create that tag as I have currently partially typed the word.

When I have finished typing absinthe I do see it as if it were a tag hint, but with a red background. Then I select it and save the post.

Then I can see the tag for some short time and then it vanishes and graphql remains to be the sole tag on the thread.