Some interaction between Firefox 1.5.0.2 and Fedora's patches (or build options) is breaking Google Reader. I've tested this with several versions of Firefox (starting from empty profiles), and I'm pretty confident in my assignment of blame. (AMD64 firefox-1.5.0.2-1.1.fc5: broken; i386 firefox-1.5.0.2-3: broken; the official i686/Linux Firefox 1.5.0.2: works fine) To reproduce: go to reader.google.com, subscribe to a few feeds, switch "Read items" from hidden to visible (so you have some history to work with), and then start clicking on up/down or pressing j/k. Instead of smoothly navigating to the next or previous item in your reading list, Reader will stop part way through the operation or jump around somewhat randomly. I'm attaching some screenshots to illustrate the problem.
Created attachment 128007 [details] the starting state
Created attachment 128008 [details] the end result of navigating down once in a good Firefox
Created attachment 128009 [details] what actually happens in Fedora builds
I retested with firefox-1.5.0.2-1.2.fc5 and this bug still exists.
running with MOZ_DISABLE_PANGO doesn't help
still happens in firefox-1.5.0.3-1.1.fc5
The new Yahoo redesign (just about everything dynamic on the page -- click on the content tabs, click on the "All Yahoo! Services" button, mouse over the Mail/Weather/etc. buttons on the right) and the new slashdot redesign (the sidebar expanders and login expander) are also broken in Fedora's Firefox. It looks like anything that dynamically resizes content breaks, although I think there's more to it than that.
The custom scrolling widgets on www.nintendo.com are also broken.
firefox-1.5.0.4-1.2.fc5 is also broken
firefox-1.5.0.6-2.fc5 still broken
firefox-1.5.0.7-1.fc5 is still broken
firefox-1.5.0.7-1.fc6 seems to work without these problems...
I tried it again with a new profile and it's still broken. I also tried it with the official Mozilla Firefox build, and it still works. I also tried it with the i386 Fedora version, and it works. So I guess the guy I conned into testing i386 Firefox was wrong and this is only an AMD64 problem, and not necssarily only with Fedora -- it's just that Fedora is the only OS shipping an AMD64 Firefox. The fastest way to reproduce the bug these days is to go to www.nintendo.com, navigate past the "You don't have Flash" page, and then click on the scroll arrows in the Hot News box on the lower left of the front page. The first click will sort of scroll it (but not as much as a functional version of Firefox), and each additional click will do nothing.
Appears to be fixed in Firefox 2.