I'm seeing an issue with CSS on Firefox (22, Windows) where the little triangles in the new tag icons are bleeding through popups.
Here's a screenie:
I have not checked it in other browsers.
You have caught my attention on this one. A fix has been pushed and will build out soon. I also want you to know that our design team has been hard at work at converting all of our .less files to a consistent and uniform layout which will solve most of these issues in the future. Thanks for the report and we'll keep you posted on the status of the conversion.