I just ran across Aza Raskin's interesting usability puzzler about how tabs in Firefox should work. It is a very interesting read, especially some of the comments, and is directly related to the problem of how to improve editor tab management in Eclipse.
Firefox 1.5 had a single row of tabs that were visible all the time. Each tab shrunk equally as you opened more tabs than could be shown with complete titles. This works well for a small number of tabs, and degrades gracefully as you open more tabs. However, it does not scale to a large number of tabs - after opening twenty or so tabs, the space for each tab is just too small and users won't be able to tell which tab contains which web page.
Firefox 2.0 tried to solve this problem by only showing a limited number of tabs. Essentially, what you see is a scrolling window into the complete list of tabs. There are buttons for scrolling left or right, and a drop-down menu at the far right allows you to see the full list of open tabs as well as jumping to a particular tab.
Aza criticizes that the new tab behaviour is concealing information, and that it makes it harder to navigate between tabs because of the added UI complexity - i.e. the scroll buttons, the drop-down list. My mother tongue German has a useful composite word for what happened: "Verschlimmbesserung" - making something worse in an attempt to improve it.
Of course, his criticism applies to Eclipse as well. The drop-down menu in Firefox is comparable to the one in Eclipse which opens when you click the chevron, or press Ctrl-E. The scroll buttons do not appear in Eclipse - instead, it uses a logic which will show only the most-recently used editors. This appears to work for some users, but it also drives other users nuts (including myself) because it is practically impossible to predict what will happen to your tabs as you switch between editors. All in all, I'd say that Eclipse has at least as much added UI complexity as Firefox 2.0 over Firefox 1.5.
The Mozilla/Firefox developers are watching the conversation, and I would encourage interested others in the Eclipse community to do so too. I enjoyed reading the discussion in the comments, the proposed solutions, and even some cool mockups. Hopefully, I'll have some more time next week to write about the more interesting proposals for Firefox and what I think we can learn for Eclipse.
Until then, I will be using Vertigo, an extension for Firefox that shows tab titles in a vertical sidebar, to see how well it works for web browsing.