Effects in Audio Mixer

I am having trouble trying to add an audio effect in the audio mixer. The manual says "To display the Effects and Sends panel in the Audio Mixer, click the Show/Hide Effects and Sends triangle at the left of the Audio Mixer."  I do that and the panel appears, but I can't find the Effect Selection triangle to choose an effect from the pop-up menu.  All the tracks are shown as blank grey rectangles without a triangle in it. I'm using CS4.2.1