What is this sell button and how do I make it go away? (Android)
UPDATE: Stopping and reopening the app fixes this. It needs to actually stop though, you can't just switch apps and reopen. Either wait for it to close on its own or force stop. I did not try the main menu method as suggested, though. It may be easier.
You may have to click the card in question, depending on your mods you can sometimes do stuff against multiple jokers (like attach jokers to other multi-sided jokers)