I've had sporadic problems with my phone locking up or otherwise behaving badly when switching between portrait and landscape.

I was using the new task manager to kill Opera 9.5 beta which was behaving badly after such a switch today and I noticed Reader taking up 80%+ CPU power. It makes sense because it has to reflow the entire book when it switches orientation, which takes a couple minutes.

I'm not sure how to fix the problem, though. I'm reluctant to exit Reader because I'll frequently read a few pages when I have some time to kill. Ideally the application wouldn't update the orientation unless it was active, but I doubt that can be achieved.

Is there some way to exclude an application from rotating? Is there a way to lower CPU priority for an app?

Maybe it's just time to switch Readers. Microsoft Reader hasn't been updated in years and it's getting a little stale. On the other hand I like the basic interface and it's easy to find books for it.

Anyway, if you ever leave Reader running it's an issue to be aware of.