As I have often professed, I am a dedicated supporter of Mozilla, especially their browser, Firefox. The first beta of the forthcoming version just dropped yesterday, despite an earlier false start. I, of course, downloaded it to take it out for a spin.
The first thing I noticed is that the Linux version hasn’t really seen very much UI love. Enough has changed that the OS integration theme I was using to make it fit in a little better with KDE is thoroughly broken. I do, however, very much like that the add-on manager now opens in a proper browser tab. I actually could see a lot more of the preferences handled this way and hope that is the future direction. Being a devoted user, I have tweaked around with the “hidden” configurations such as about:config. While the add-on manager doesn’t expose any more options, the greater space available makes it feel less cramped.
Unfortunately, as much as I would like to switch over to the Firefox 4 beta for everyday use, there is a rather distressing breakage on 64-bit Linux. Flash is totally inoperable, I suspect as a result of my having the abandoned 64-bit build installed and this first beta being a 32-bit build. I dearly would enjoy a web I could use without Flash but we aren’t there yet, so I am going to wait and see how this situation evolves with the next beta.
I may, also, in the meantime try to find or produce a 64-bit build of this beta. I don’t feel especially motivated, being very happy with the current 3.6.x packaged build I am running but I would like to help with testing and feedback if I could sort out the Flash problem say on a weekend afternoon.
Update: Thanks to @claudiom, I have Flash working. The solution in my case was almost self evident. I downloaded the tarred, gzipped version of the Flash plugin for Linux. In the local directory where I originally unarchived the Firefox beta, I created a plugins directory. I then unarchived the Flash plugin into that directory. On launching Firefox 4 beta 1, Flash now works.