There are so many customization settings provided by Tree Style Tab allowing you to delve as far as you want into a topic without missing a beat. Instead of looking at the top section of the browser for all your squished to fit tabs, you have a highly organized tree hierarchy. This add-on does not remove the top tabs but merely places them in a more organized structure. Any new tabs opened from a primary main tab are presented as children. They are displayed slightly indented, allowing at-a-glance insight into where they came from. You can rearrange them via drag n' drop if needed. Any children can be folded (collapsed) by clicking on the down-triangle shown in the "parent" tab keeping the view neat and uncluttered.
The F1 key toggles the Tree Style Tab sidebar.
The Tree Style Ta toolbar button also toggles the sidebar. If it's unnecessary, you can remove it from the toolbar.
Tree Style Tab will be the perfect solution for those that find themselves with multiple unorganized tabs cluttering their browser and want to achieve a more organized session.