and try to open a new topic, the current category I chose is not selected by the editor. I also cannot manually select “Community Extensions > palladian-selenium” either. hence, I cannot post a new topic in the corresponding category.
Yes. Neither the previous automatic approach to select the category upon clicking new post nor manually trying to select it works. I tried to verify if it‘s case sensitive or not but to no avail.
@qqilihq mentioned, as we were exchanging via email as a fallback, that „you“ recently switched some categories to tags. Since then the interaction experience drastically declined. Checking the palladian / selenium sub-category it also seems posts are created much less often (no quantitive statement, just observation).
I can verify the behavior described here, which I believe is a Discourse bug. We recently updated the forum software to the latest version, so that may have something to do with it, but I would have to check.
As a workaround, I tried creating a topic in the Community Extensions category from one of the other pages on the forum (not the specific tag link you provide above) and it worked OK.