How to use the trim feature in MSP7?

[pizor1]

I recently asked some questions about the ripple feature, but now I realize my poblem isn't with rippling, but with trimming...I think.

Using MSP7, I have 20 min worth of video edits laid down with a music track locked in A2 and multiple track ripple selected. I was able to highlight a video clip, then click the edge (the end point) and drag it to adjust its length. When I did that, the ripple mode worked as it should. However, when I double clicked on the same piece of video and viewed it in the source window, I ended up with a blank space. In the source window, I shortened my clip to the desired length, then clicked the check mark. The clip in the timeline shortened, but it left a blank space after it and the transitions didn't move.

Is there anyway to avoid this? I checked the manual, but couldn't find an answer.