emacs 24 - mouse drag does not highlight

Something else changed between 23 and 24.  How do I get the 23
behavior back?

In 24, if I down-mouse-1 and start to drag to select a region, the 
region is not highlighted until I release the mouse.  In 23, it 
highlighted as I dragged, what I consider normal for both Windows and Linux.

I don't have anything in .emacs for mouse-1.

C-h k mouse-1 says this when I release it:
<down-mouse-1> at that spot runs the command mouse-drag-region

I have this in .emacs to make cut and paste work for Windows 7 and emacs 24.

(setq select-active-regions nil)
(setq mouse-drag-copy-region t)

Also, transient-mark-mode is t.