In Jeff Bellunes screen shot (April 11, 10:21)
Look at the track header to the smal icon (4 small sqaures) that appears immediately to the left of the word :Audio in the wave form (green). If you click on this symbol, it will bring up a dialog that will allow you to assign the track that has audio to both the left and right channels. Once set, this applies to all audio clips placed on that track. You don't need to re-record each clip, or apply the :Fill Left or Fill Right effects to each clip.