[Timgrivas]

To replace a source clip in a layer with a different source clip. From the composition window/ timeline, select the layer that needs the source clip changed in the composition window. Press option and drag the new source clip from the project window and drop it on top of the selected layer in the composition window. one note: when you drag the source clip on top of the layer and drop it,,,, there is no visual indication that it worked besides the preview window changing to the new clip. but that is if the preview window is already opened.