Primatte: Why aren't any of the Primatte controls working?

There are two reasons Primatte Controls might not operate as expected:

• The Primatte effect needs to be selected/highlighted in the Effect Controls window prior to using Primatte's effect controls. Selecting Primate essentially creates a tunnel between the pixel data in the host's viewport and the effect, and also ensures no other effects (that might also operate by sampling pixel data) interferes with the process.
  
• If using After Effects, the Layer Controls need to be visible; these are found under the View menu > Show Layer Controls. Layer Controls need to be enabled on account there are large components of Primatte that are contingent their visibility (namely the sampling boxes drawn over the frame when using the rectangle sample mode).