Firefox jittery, sometimes missing keystrokes and not smoothly scrolling

Other items I forgot to mention in the first post:

As I mentioned in the header, this problem also causes non-smooth scrolling.

Another symptom is that new tabs have a noticable delay before opening. Also, I don't know if it's related, but several days ago my computer hard locked while watching an embedded flash video. All this performance degradation almost makes me want to use a different web browser.

I have been noticing Firefox also missing some of my keystrokes lately, mainly when I'm typing in the URL or search bar (for example, this entry in this textbox did not have any missed keystrokes, but as I was typing in the google search bar to find this bug, it did miss a couple letters).

I have a modern system - Core 2 Duo 2ghz, 2gb RAM, hardly doing anything else in the background. I don't see a reason for this to be happening.

I have this exact same issue.

Once or twice every second or so, a keystroke will be lost.

Restarting Firefox temporarily solves the issue, but it always come back. It seems to get worse the longer Firefox is open.

All of this with Firefox only using 5% CPU.

Man, typing this message alone was tedious and taxing. This bug is really starting to get unbearable.

Just wanted to echo previous posters: Firefox has been dropping keystrokes since I upgraded to Ubuntu 9.10 and Firefox 3.5. It is especially problematic when entering URLs in the address field and has been a noticeable detriment to my productivity.

I've also experienced dropped keystrokes. I'm not sure why, but the keystroke dropping and unresponsiveness appears to be correlated with Flash either not responding or getting sluggish.

I also use the acrobat viewer plugin, which has shown a noticeable decrease in its stability, usability, etc. with newer versions. It shows little yellow boxes with no content on the screen (they go away if you click somewhere). The page scrolling is choppy, and often results in the remainder of the page not being rendered (fixed if you skip a page ahead, then back). Like above, I have no idea if any of these issues are related, but they tend to happen at the same time.

This has been hurting my experience for almost a year now, on two separate computers that aren't similar (notebook & desktop). Specifically, I mostly experience the problem when typing in the address bar, which is quite noticeable as I often end up going to gogle.com or goole.com. I don't have much else to add, besides further confirmation of the problem.

I'm on 10.04 with firefox 3.6.12 and it's only the URL bar that is dropping keystrokes. I notice this rarely (like one every couple of days). Only happens to me in firefox and only the URL bar.