After selecting a preset transition, when I try to drag it to the timeline I get a round circle icon with a crossbar thru it and the transition won't move. Happens to all of the transitions. The Effects all work fine, as do the audio tracks, etc... just the transitions. Doesn't appear to have anything to do with what media's in the timeline, tried different projects, even when the timeline is empty that icon appears after the transition is selected and as soon as I attempt to move/drag it. It won't let me use any of the transitions. Why? How do I correct it?