These are all very interesting, and I can definitely see some people who would prefer Chrome's "tabs on top" approach with respect to Firefox's. However, personally I've never found much attraction in the other aspects of Chrome's GUI. I like its "tabs on top", but other than that, I don't like how it eschews the native application colors and decides its own ones instead. Probably just a personal quirk.
I will also say that the best part of Chrome isn't really its GUI, but rather its mind-blowing speed. If Firefox could become a Chrome-clone in terms of speed, that would far more beneficial than just cloning its GUI. Chrome's speed puts it into the leagues of a usable browser, and Firefox with Chrome's GUI will only make Firefox slower (more extensions always does that, no?), and slowness defeats the purpose of having a Chrome clone.
I don't know, but this seems like a bunch of fixes that aren't really worth the effort unless someone is truly, truly obssesed with Chrome's GUI. But most people, after Chrome's release, were excited more about its speed than GUI. In fact, if Mozilla goes to great lengths to make Firefox faster (say they start using the same Javascript engine Chrome uses), then it will become a lot more competitive in the speed department, not just with Chrome, but also with Opera and Safari. Sometimes it's sad how Firefox is such a slow browser, but I can't switch away from it due to allt he customizations that I've already added into it.
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