Unable to edit Product Flow in Process Management

Hi,

I’m trying to rearrange General Operations so they are parallel.

The problem is that I’m unable to edit, delete, or create product flow links for some reason.

Links are created according to the operations sequence in the tree, and I can’t manage them.

 

I’ve noticed, that in the Parent Workplan and Header Operation, the Sequencing Mode is set to Linear, but I can’t change that either.

 

Any ideas on what might be going on here?