Composer GUI while open effects performance on Simulator

G’day all,

I’ve started a new game using the Composer GUI and when I save it and preview it in the simulator the assets / animation move pretty slowly.  It’s almost like it’s running at 30 fps (even less) when in fact I’ve set the project up to be 60 fps.

When I close Composer GUI the smoothness of the animation returns to expected levels when set at 60 fps.

Has anybody else seen this?  I’ve got 16 Gig of Ram on my powerbook.  I’m also using the latest build of the SDK (2015.2646)

Any settings / ideas of how to potentially fix this?