Rated 5 out of 5 stars

Very useful extension indeed!
I'd like to request two features:

1. Make optional auto-faviconizing the tab when I pin it.

2. When tab is locked it would be usefull to make an option to allow browsing inside the domain I locked the tab to. Clicking on link to other domain opens it in new tab.

I believe these requests are not that hard to implement :-)

This review is for a previous version of the add-on ( 

1. You may un-faviconize a tab after pinning it.
2. The "Force all external links to open in New Tab" option may be more suitable for you.