Thanks for the link.

I also found this at the beta page:

"fps_max now uses a CPU loop for small idle times, which reduces the 'stuttering motion' problem on levels with high frame rate."

Is this a very fast reaction to the jerky camera problem of the lighting demo?

If that is the case then I would like to thank for this fast reaction. This is great.
So making official demos is really a good decision to realize real problems on real projects and overcome their issues.
This is the right way. Thanks.