The interface at https://trello.com/u/username/cards was way better before. What happened? Now you can't apply more than one filter.
They changed it, looks like some merging of styles with Jira, it has cause a lot of irritation amongst users so they have at least enabled a way to switch off the new view...
Go to:
Then turn off New cards page...
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.