Since installing MOUNTAIN LION, there has been a change in the FINDER TOOLBAR which I liked having available with LION.

Under FINDER / FILE the option to open a file using "open with" is GRAYED OUT. But default, all document files are now opening with the Text Edit app - regardless of the format in which these were saved. In LION, one could change individual documents to open with different applications, but that feature is no longer active in MOUNTAIN LION's FINDER.

How do I 'unlock' FINDER so that I can re-activate the "open with" option?

Thanks.