Maybe I've never noticed this before? Does an imported video object with no audio content always occupy two tracks, the lower one being entirely redundant? (I never enable Video/Audio on one track.)
I've been editing a few animated symbols I made as WMV files. Despite exporting as Video, not 'Video+Audio', when re-imported it always occupies two tracks. I always ungroup and delete the 'audio', but I'd rather not have to do so.
Program Settings > Video/Audio > Import video with sound is enabled, as I naturally want my recorded video to be imported with its audio.
Terry, East Grinstead, UK