In 10.1, if Constraints Editor standalone is used to open a project from ISE 9.2i, a dialog appears to tell the user to use Project Navigator to update the project. Then after this dialog, the standalone dialog appears. If I continue to load the project, the same message to use Project Navigator to update the project appears.
This problem has been fixed in the latest 10.1 Service Pack available at:
The first service pack containing the fix is 10.1 Service Pack 2.