I notice that the animated tray icon of Kopete is quite cpu hungry when compositing is enabled. Is there any way to disable it and, preferably and at the same time, to have an non-animated notification. In fact, the notification becomes non-animated after some time, and I would like this to happen all the time by default.

I'm not sure if this is what you search for:
Do a right click on the tray icon->Settings->Behavior->Events
There make sure that the first option ("Animate tray icon") is not set.
The names can differ because I translated them from German.

That's somewhere I should've checked. Thanks.

Actually this is not quite what I wanted. If you disable the animation you disable all notification in the tray icon. I was more hoping for a non-animated notification.