AnimationTimer and actual frame rate

[Michael Paus]

Hi all,

for quite a while now I am observing a strange behavior when running some

JavaFX graphics tests. The scenario is very simple. I am running some 
animation

which puts some load onto the graphics engine and I am trying to measure the

frame rate via an instance of an AnimationTimer. When I increase the 
load high

enough I reach a point where the indicated frame rate is just 60FPS or 
even a bit

lower but the observed frame rate on screen has already dropped to something

like 1-2 FPS. So what I observe is that the AnimationTimer is running 
much faster

than the updates of the graphics. How can that be? Does anybody have an 
explanation

under which circumstances this can happen? Or is this behavior a bug 
which I should report?

Just some puzzle for the boring Christmas holidays :-)

Merry Christmas to all of you

Michael

PS: My system is a MacBook Pro with NVidia graphic card.