When setting your DAW up for RAVEN expanding the work space window is frequently used. In the most recent OSX update, El Capitan 10.11, the green "+" button now enables "Full Screen Mode". RAVEN cannot be used in "Full Screen Mode".
Follow these instructions to properly maximize a window:
Maximize a window: Hold down the Option key while you click the green maximize button in the top-left corner of an app window. To return to the previous window size, Option-click the button again.