Can’t drag sub-assem on pin connections

[pro_eek]

I have a fully constrained part with holes. I add 2 sub-assemblies by using pin connections. (hole axis in sub assem aligns with hole axis in main part, faces are offset)
When trying to drag the sub-assemblies, a point is highlighted on them, but one can't drag it.
I assembled another single part in the same way, this one can be dragged.
?????
(By the way, this has prompted me to post my observations on pros and cons between Pro/E and Inventor.)

 

[pro_eek]

My mistake, I had the stuck parts also assembled to something else, which is why they didnt move.