Mouse will not drag files - it draws a selection box instead.

The "drag and drop" stopped working in the middle of a session.

If I try to use the mouse to drag a file in the content window to a different folder, Bridge draws a "selection box" instead of moving the file to a different folder.  The same thing happens if I try to drag files into a different order in the content window to prepare for a batch rename.  It was working fine then suddenly changed the mouse behavior.

So far, I have:

- updated to the latest version (11.0.2.123) of Bridge

- restarted Windows several times.

- uninstalled and reinstalled Bridge (twice)
  This included a sequence of 1) Uninstall, Run CCleaner, Restart Windows, ReInstall Bridge immediately after restarting.

- Verified that the mouse works properly in Windows explorer, Excel, MS Word.

- Cleared the Cache in Bridge.

- Attempted to use drag and drop in several different folders.

  This occurs using with files on the main drive, not a removable drive.

I am a new user, so it is quite possible that I somehow incorrectly set an option someplace. 

HELP. I have 500 new scans of family photos to sort and do batch renaming.