Trailers clip alignment

I am working in the Epic Drama trailer, and I am having troubles with my clip alignment. I select 4.2 seconds (or whatever I need for the next shot), but often there is bleed over into the previous or next scenes. Is there anything obviously wrong that I am doing? Could I have a framerate mismatch?

Also when I click the "Click to adjust the portion of the clip that is used" button to try fine tune to correct this, in the clip trimmer view there are often what appears to be two different selected areas: a larger selection (with a thin yellow line) and a smaller selection (with a thick yellow line). What is the difference between these two selection areas?

Thanks,

Todd