Hello, I created a simple pump and impeller. Then I assemble them to do flow simulation. For that, I created another component say 'Boss-extrude3' to apply to rotating region and while creating this I unchecked merged option. Also, in component control, I disable this 'Boss-extrude3'. Then I went to select rotating region but I am unable to select any part. What am I doing wrong? In select another option, Pump only is appearing. Images are attached to it.