I just installed IM.  I have changed the units under preferences to feet, yet the ruler on the world space tool still displays the length in meters.
 
Any way to change that?

Hello,
 
  Yes, even though in the tool options it is correctly converted, in the 3dview its always in meter. This is a bug, but only a display problem, as all the measures that you'll make will be in inches.
We will fix that in later releases.
 
Thanks,
Stef