user17433: I have a simple video with some background noises added and a background audio track.
However, background audio track is too long, so I carefully cut it into multiple pieces and seamlessly mix:

It works fine, but my second audio part is now connected to the video on top — every next change in the timeline will break my carefully mixed audiotracks.
I want it to be connected to the first audio part instead.
Is it possible?

user20675: Create a compound clip with the music on the audio track. This will fix them in place. Replace the individual clips with the compound clip. 

17433: <p>I have a simple video with some background noises added and a background audio track.<br>
However, background audio track is too long, so I carefully cut it into multiple pieces and seamlessly mix:</p>

<p><a href="https://i.stack.imgur.com/woT7t.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/woT7t.png" alt="Final Cut Pro X — Mixing Background Music"></a></p>

<p>It works fine, but my second audio part is now connected to the video on top — every next change in the timeline will break my carefully mixed audiotracks.<br>
I want it to be connected to the first <em>audio</em> part instead.<br>
Is it possible?</p>
 20675: <p>Create a compound clip with the music on the audio track. This will fix them in place. Replace the individual clips with the compound clip. </p>
