What happened to Single Window Modeling

I just downloaded the new build of RhinoOSX and the Single Window Modeling is gone. I tried the command suggested in the previous build - TestSingleWindowModeling - and it said I now need system 10.8 to use it. I use 10.7 and it worked just fine in the last build. Single Window Modeling is much more efficient than the old navigation system. Help please.

Continuing the discussion from First look at single window modeling:

See the first paragraph of this top level post Single Window Modeling.