How to remove a little "connection" between clips in 2 tracks in iMovie? This is the square I mean. I know what is it for. It means that two clips have strong connection in these particular places. But now I need to remove these relative connection:-) The question is HOW?
You can't. Audio tracks are attached to a specific video clip.

You can move them though: hold ⌥⌘ and click somewhere on the audio clip.