Free Select tool should create preliminary marching ants selection
Free Select tool in 2.10 is now more consistent with other selection tools, now that it allows tweaking poly nodes' position before confirming the selection. However, unlike other selection tools, it doesn't create a preliminary marching ants selection. So while users can copy a rectangular selection without confirming it, they can't do it with the Free Select tool.
This is one of the major griefs I've seen users have with 2.10. Let's removes some more friction, shall we? :)