Paul LS wrote: Transitions need "cut" frames at the end/beginning of the clips to use for the transition.
If you have only "cut" one of the clips the transition will put it self on that clip... and use repeated frames from the uncut clip for the transition. To overcome this cut a few frames from the end of both clips.
If your transition is 1 second you would need to cut 15 frames off each clip (30 frames/second).
Joe wrote: is there an easy way to do this? Sounds kind of time consuming if you have a lot of clips
Rene wrote: Click on Show Timeline.
Now you will see an A/B timeline in the properties window.
Go with your mouse to the first clip in the properties window, till you get an red braked, now slide that to the end of the transition. Do the same with the second clip, but now slide to the begin of the transition.
Rene has put together a very nice demo of how this works: