I don’t know about in the event browser and can’t think of when you would need that (but I am a hack and no doubt it’s something you do ALL the time for good reason) but if you drop it into the timeline and select the trim tool, you can slide by grabbing the top edge of the clip (the tool becomes something which looks like this (<-I->) with the traditional film strip/slide icon underneath). You likely knew that already, but it is so sad to see your question sit unacknowledged. Happy cutting.
Jordan Cushing
Director of Photography
London, UK
http://www.jordancushing.com