FCP: I've lost automatic clip docking in the sequence
 

Hope someone knows the answer to this. I've noticed on a few FCP projects, including one that I'm currently working on, that when the project gets large, I loose the auto docking facility in the sequence, i.e. when sliding clips along the timeline, you don't get that automatic alignment of the beginning of one clip with the end of another. It turns out that it's real useful, otherwise you can end up overlapping or with a black space between them. Anyone have any ideas what might have happened?
Thanks!

The feature is called "snapping", and N is the keyboard shortcut to turn it on or off.

Almost every key on the keyboard is a shortcut to something or other in FCP, so you have to watch your P's and Q's (literally).

Nate thanks, sounds like may have switched it off accidentally when doing a freeze-frame generation.

I normally have 'N' snapping turned off by default. You can snap to edit points on the timeline using the up and down arrows to move forwards and backwards between edit points.