It stopped working at some point.
I think it was in 17.1 beta, but I'm not sure.
To reproduce the problem:
-Start a new project, then place some background element (a image, video, solid color generator, etc) that covers the whole screen at track 1;
-Place a solid color at track 2, over the background element:

- Resolve post 1.jpeg (14.18 KiB) Viewed 515 times
You should be seeing a black screen by now.
-Then, select the solid color, and apply some cropping, so that you can see some part of the background:

- Resolve post 2.jpeg (144.32 KiB) Viewed 515 times
-To finish, select the solid color, and make it a compound clip:

- Resolve post 3.jpeg (14.88 KiB) Viewed 515 times
The result will be a black screen.
If you decompose the compound clip in place, the cropping will work again.