The following describes known limitations related to the user interface.
Mudbox remains in front of other applications when switching between applications on Mac OS X
Switching to another software application when running Mudbox and the tool cursor is positioned over any tool tray will result in Mudbox remaining in front of the other applications preventing use of those applications.
Workaround: Move the tool cursor away from the tool tray region prior to switching to others application when using Mudbox on Mac OS X.