Dear Isadora Community,
Thanks to the insight and feedback of our Isadora users, the TroikaTronix team has discovered a critical issue which negatively impacts Isadora's performance under Mac OS X Sierra. The source of this performance issue appears to be an undocumented change in the way Sierra renders Isadora’s user interface text. As a result, projects which use a very large number of actors, or actors which feature many properties (such as the 3D Particle Generator), may experience significant frame rate loss under Sierra when dragging actors or scrolling the user interface. This slowdown is non-existent or negligible if you are not actively editing your patch.
While we are aware of the issue and have solutions in the works, a permanent fix for this issue is still under development. Until we have more information from Apple on what exactly is causing this issue, or hopefully a fix from Apple themselves, we strongly recommend Isadora users avoid upgrading their Mac computers to OS X Sierra.
At this time, we have not encountered this issue on Yosemite or El Captain. Isadora users working with either OS X 10.10 or 10.11 can and should continue to use these operating systems with confidence.
Thank you for your patience, understanding, and support while we continue to work to make Isadora even better.
The TroikaTronix Team