When I have anothe window above Firefox and scroll, the page gets completely messed up, and this is extremely annoying.

This does not happen in Konqueror.

See attachment:

That is strange. Have you tried disabling all your add-ons (if you have any,) and restarting it?

The only add-on I have is AdBlock Plus, I still have the same problem if I disable it.

I believe that his happens when there is not much RAM / video memory... I'm not sure though. I have seen it on both Windows and Linux machines.

My video card is about 2-3 years old, made by HIS, and uses an ATI Radeon HD2600, but I don't know the amount of video memory it has, though. I would guess 512MB, but I really don't know.

I don't know if you are talking about RAM, but either way that couldn't be the problem because I have 6GB and I don't remember using more that 1GB.

Still is there a way to fix it?

Is your card capable of 3D acceleration? If so, you could try using a hardware-accelerated window manager (such as Compiz, if you're not already using it). That type of "blit smear" is what you get when the WM (and/or the application) fails to redraw the contents of part of a window that was obstructed by another window, and is usually an artifact of a stacking window manager; at least that's what I've noticed.

Gurus, please correct me if I'm wrong about this (but please go easy on me...I'm not intending to misinform anyone)

Adobe Flash is so buggy at times, I wonder if that might have anything to do with your problem, even indirectly.


Edit: Just throwing ideas out there.

Yes, I do have 3D acceleration (Radeon HD 2600, Free X.org "radeon" driver, Mesa).

Is a stacking window manager the type of window manager that lets X itself do the stacking, as opposed to a compositing WM?

I do not have Flash or any Free substitute of it installed. I would like to, but it is such a pain because Flash is non-free and to watch YouTube Gnash needs non-free parts.

I really wish YouTube could use Ogg Theora and <video> tags...

I'm a little sketchy on the exact details, but AFAIK yes, I think that's what a stacking WM does... What desktop environment are you using? It looks as if you're using KDE, and I think KWin (I think that's what it's called) is *supposedly* a compositor, but it might not be HW accelerated (I have no idea about this; I haven't used KDE much). I'm using GNOME, and I'm not sure if Metacity is a stacker or a compositor, but I do know that if you have a program open that requires a lot of redrawing (such as Firefox), then moving a window around on top of it tends to smear the graphics at least temporarily; depends on the speed of the machine, I guess.

Anyways, enough rambling I think if you can get Compiz to work, that would be great, as then all open windows are rendered into separate buffers in video memory, which *should* alleviate the smearing problem. At this point, I'm not sure what else I'd do. I have Compiz enabled on my machine, and not just for the fancy animations, LOL.

Hope all goes well!

I hear you, definitely. Flash is such a resource pig; my CPU usage soars to nearly 100% while watching YouTube vids.

Enabling Compiz did stop the smearing problem, but the scrolling is a bit jerky now.

Not to mention it's not Free/Open Source and a big pain on x86_64.

EDIT: Is there a way to get more fine-grained control on Compiz, not just the "wobbly windows" and "desktop on a cube" checkboxes in Fedora?

Install CompizConfig Settings Manager (ccsm). You should be able to find it in your software repos. It allows you to enable/disable/tweak just about every plugin Compiz has. It should be more than "fine-grained" enough

I tried installing ccsm, but whatever I do doesn't seem to take effect. For example I click on the "Wobbly Windows" checkbox and it doesn't change anything. There doesn't appear to be any kind of "Apply" or "OK" button.