Sorry, I guess I messed up the first time.
I'm losing confidence about the integrity of the design file.
There's a component (EasyTube) with a RigidGroup that contains the clamp that I was having trouble with and three other components. The components in the rigid group are selected using "Select Components" after right clicking on the RigidGroup.

First strange thing--
I was able to join the clamp component to another component ("top section") and only that component moved. If the clamp component was really part of a rigid group, all of the components should have moved along with the clamp component when the joint was done.
I thought maybe this was because I created the clamp component as a child to the "Easy Tube" component AFTER the other child components under EasyTube had been defined as a RigidGroup. Maybe I need to fix that somehow to avoid confusing F360?
Moving on, I then tried to move the rigid group, assuming it really didn't contain the clamp component. I got different results on subsequent retries of what I think were attempts to move the same component.
Sometimes, the grounded component "T-bar" moved along with the rigid group and clamp moved with it. After undoing and retrying I got everything but the clamp component to move while the T bar stayed but (what I really want).
Anyway, the design is getting bigger all the time. If I'm going to have to start over, better sooner than later.
I can do a gif on that shows the unexpected behaviour of the rigid group and/or grounded component if the explanation above isn't clear.
Thanks!
