Rated 5 out of 5 stars

This looks like an ideal solution to facilitate efficient use of TB.
I have 23 email accounts that I use, and I use unified view all the time. I would love to add an extra pane with my favorite folders in it. This way, I could take advantage of both the unified view AND be able to use folders efficiently. Now, the use of folders is out of the question, because they are buried down deep, and I never check them.
I would gladly pay to someone who could come up with the same solution that would work in TB3+.

This extension is seeking for a new maintainer. If you find one, let me know! http://code.google.com/p/afview/