I am posting this from the mobile app as I am not able to post any questions or edit tags from the web interface. After writing the question I am not able to select a tag. Writing the text
bug also does not help. When I hit the post I get the message
You should select at least one tag.
I get the same behavior on both Linux (Ubuntu 14.04) and Windows (Server 2008 R2) with both Chrome and Firefox. I think this is a very serious issue as posting questions/tag edits are core functionality.