Problems with NSViewAnimation and NSTimer

[Fred Kiefer]

I just switched the implementation of NSWindow setFrame:display:animate: 
over to using an NSViewAnimation. The reason for this was that the old 
blocking code could yield wrong results as intermediate setFrame: events 
send from the backend would not be processed during the animation and at 
the end the window could end up in a messed state.

With NSViewAnimation I first had the problem that this code was not 
prepared to ever release an NSViewAnimation, this was easy to fix, still 
I needed a helper object that will release the animation when it ends. I 
was hoping that I could release the animation after starting it and then 
rely on it to free itself up when it gets stopped. But this wont work 
with our current code in NSAnimation and with all the lock handling 
scattered in there I did not dare to change anything.
With my helper object things basically work, although I am not sure that 
in a garbage collected environment the same will be true.

Not there is one remaining problem. When I start the animation it 
registers an NSTimer itself for the run modes NSDefaultRunLoopMode, 
NSModalPanelRunLoopMode and NSEventTrackingRunLoopMode. When the 
animation gets stopped the timer gets invalidated and will be removed 
from the corresponding run loops later on. But as there is no 
NSModalPanelRunLoopMode going on in my test application it never gets 
removed from that list and I end up with all these timers living 
forever. Not that I care much, even a few hundred timers shouldn't stop 
that application from working, still it looks wrong to me.