firefox CPU load

[Erwin Rol]

Does anybody else see the following behavior? I have two tabs open in
firefox, now i try to load a real slow page in one tab. When i select
the tab that is loading the page the CPU usage is about 50%, when i now
switch to the other tab the CPU usages goes to <1%. While loading there
is nothing on the page yet that could cause this CPU load, just some
text. The only difference seems to the the animation of the icon in the
menubar, the icon in the tab is animated even if the tab isn't
selected. 

- Erwin