Black between clips of compound

I have 5 MP4 clips on timeline. Selected, and set Alpha Mode to Clips attributes.
1st, 3rd and 5th are selected and create a compound clip.

Result:
The selected clips are moved to a higher track and are compound.
Between the clips of the compound clip, there is black.
In the compound timeline, the gap between the clips are empty.

Expected result:
Between the clips of the compound clip, there is transparency.

Hartmut

[Peter Chamberlain]

This is working as expected. Compound clips cant be made with other layers within the compound.