Gaps don't remain seperate

Hello,
I have placed multiple gaps one beside the other. At a certain point when I add images my
underlying gaps all unite to become one unique gap.
Is this normal?
I want to keep them seperate. I'm not using Placeholders as I want a black backgroung.

SOLVED: I simply can add a Placeholder with a black backgroud...Pretty obvious once you see it!

Not really. They should remain separate, but it might depend on what's happening in the timeline. Could you post a screenshot? I'd be curious to see what's happened. BTW, gaps are not black; they're actually transparent. If you export without an alpha channel the background will be black.

Thanks.
I meant gaps look black.  I tend to forget about the transparency!
I just changed all the gaps to placeholders.
I will try this on another timeline and post it here later.

I haven't tried but if I put a placeholder with a black background will it be black when I render ?
I would'nt need to put a black image. Just curious.