Trying to select and move a group of components on a PCB design by drawing a bounding box to select and highlight.  When I do this, various other random components outside the bounding box are also picked up and selected, then "move" shifts all of them which is very irritating.  How do I prevent this behaviour please?

Grouping the required set of components does not alter this behaviour. I want to select a group of components and move only those.