When a Movie file is selected, clicking the edit button in the toolbar does nothing - it should open the Movie file in your video editor of choice eg. KDEnlive or PiTiVi.
Likewise, when an audio file is selected, clicking the edit button again does nothing - it should open the Audio file in your audio editor of choice eg. KWave or Audacity. Integration is one of KDE's great strengths and little things like this make for a more cohesive and satisfying end user experience.