The following bugs have been fixed:
1) A build error in 2.0.10 resulted in an application that would only run under OS X 10.6 (Snow Leopard). This build error has been corrected, and 2.0.11 should run correctly on all versions of OS X from 10.4 onwards.
2) The corrections to allow better performance of the GUI while rendering in the background caused a degradation of the performance of rendering. Changes have been made to partially correct this. The edit window fractal generation should be very fast now. The background rendering is now probably at par with its previous performance, but greater speed with mulitple cores is still possible for anti-aliased images. Further speed increases will probably be made available in the next version.