Some embodiments of the invention provide a media-editing application for creating and editing a media presentation that displays the results of edits as the edits are made to the media presentation. The media-editing application displays the movement of media clips of the media presentation as the media clips are being moved within the media-editing application to change the media presentation. Also, the media editing application in some embodiments can dynamically display the results of edits in a preview display area. That is, the media editing application has a preview generator that can generate previews of the media presentation on the fly as media clips are being dragged into and within the timeline. This allows the user of the media-editing application to see and hear the results of the operation while performing them.