Under 'Default Java for browsers' there is a checkmark right next to 'Microsoft Internet Explorer'. This option is greyed out so the checkmark cannot be removed even if I wanted to. But next to the 'Mozilla-series' option there is no checkmark. But if I check it, the cahnges cannot be applied. When I check it, click Apply and then OK and reopen Java control panel, it is still unchecked! So it seems as changes cannot be saved.
I tried this actually before. It is described in a Java help article.
Java help article on enabling Java for browsers:
http://www.java.com/en/download/help/enable_panel.xml
Under the Java Plug-in it says "Enable the next-generation Java Plug-in (requires browser restart)". It is already checked and greyed out, so I cannot remove this checkmark.
I have tested Firefox 4.0 RC when it was released. I installed it in conjunction with Firefox 3.6.18, but in separate installation folders, which still caused some conflicts between the two. For instance, clicking the Firefox icon on the Start menu would once start Firefox 3.6.18 and once Firefox 4.0 RC. And both of them were experiencing things like situations where it would just stop responding for about 10 seconds every now and then, while surfing the web. But it would come back to life after about 10 seconds.
But like I said this had to do with a conflict between the two. However, I experienced Firefox 4.0 as very slow. It seems to be graphically more heavier than its predecessors thanks to the many new features it introduced. I did not get that same speed and responsiveness as with FX 1.x, 2.x and 3.x. I feel like they have changed the focus completely now, it's as if they are copying Opera and IE now. As if they have left their roots of being the most speedy, responsive, and lightweight browser, which is what I liked most with Firefox.
I have been using Google Chrome for some while, and right now I think it's the fastest and most responsive browser out there. I think it could replace Firefox on my computer. The new IE 9 by the way is also very fast, for being IE that is.
I did not test the new 5.x version of Firefox. What's up with these new version number schemes anyway? Evolutionary this new version should not be too much different from 4.x. Why don't they drop the bomb and call it Firefox 9? To make it more close to IE, Opera, etc. you know?!...
When can we expect a 64-bit version of Firefox anyway?