Firefox, I Just Can't Quit You

I open a lot of tabs.  I am sure many Hacker News users are the same way.  My work flow is to open things that look interesting in HN or Google Reader, and later on I will read longer pages when I have time to get absorbed in them.

Using more than a half dozen tabs in any browser gets hard.  The title of the page is no longer visible and you're left with a thin sliver of favicons across your top bar.  More over, if I have several windows related to the same project, it's hard to switch between them unless I keep them tightly ordered together.

Tree Style Tabs fixes both of these problems.  All of your tabs are laid out as a hierarchical tree, docked to the side of your browser.  Anytime you open a link in a new tab, it shows up as a child of the page you opened it from.  All of these children can be easily collapsed.  If several pages are related to a project you're working on, you can drag and drop them together in the tab docking area.

Chrome has several plugins that try to do this, but they do not have dockable panes as part of their extensibility model.  This totally negates the at a glance benefit you get from Tree Style Tabs in Firefox.