Resolve 15.1.2 - Problem with Fusion / Compound Clip

As Resolve requires a compound clip to work from, creating a fusion clip can be achieved by generating a solid colour clip from the Effects/generators and converting to a compound clip. Great so far.
However, if I discover that my clip is too short, it cannot be extended. It can be shortened but not extended. I have to create a new compound clip and start all over again. Is this a bug? Is It intended to be this way? Have I just not found the way to extend the clip?

Instead, use the "Fusion Composition" from the edit page > generators. This will allow you to extend your comp retrospectively. I think this is a recent addition.
DC

Thanks, that works fine.