[namtih]

Ah this produces high CPU because the title doesn't fit, and it has to scroll.
That's fair enough - the dirty rectangle rendering means the whole display has to be refreshed because this is constantly changing.

However after this, I highlighted again "X-Men", now there is no scrolling text, but the CPU is still high.
I can move away from Movies and the CPU goes down, but whenever Movies is highlighted, even though there is no scrolling text, the CPU is high.

You can also reproduce this scrolling bug within the addon menu while using the list view.
When you scroll through your addon list and come above an addon with a long description, the CPU will stay at 97% even when you select another addon. You can only stop it, when you completely exit the Addon menu.
My personal work-around currently is, that I edit all addons with an long description text and remove it in the according xml file, so that no scrolling happens.
The RSS feed with the scrolling text is also such no-go.

I think it would really help a lot, when the handling of dirty regions could be approved. I think it would also improve the speed of the overall XBMC interface as you could use "algorithmdirtyregions = 1", which unfortunately only produce/big massive artefacts at the moment.