Transition causing grief

OK, getting used to fcpx....slowly.....BUT

My workflow has typically been to rough out all the clips into my basic structure, then polish the film after by adding the transitions I like. Worked great in the past.

But, in fcpx, when I do that, the cross dissolve (or any transition for that matter) starts to shrink the time line (sorry, story line). It's throwing my timing way off.

I'm using 24fps full HD.

Any ideas from the experts?

Thanks.

In your preferences, Edit tab, change the
transition setting to 'Available Media'

Full overlap forces FCP to trim your storyline
to enable default transitions but you are experiencing the unwanted
downside of that mode