I posted this question in another forum but I didn't get a response.
The last two versions of Kliment's Printrun Pronterface that I tried using with RAMPS and Sprinter doesn't seem to be responding to the home (G28) command correctly. Clicking on the Home X, Home Y or Home Z buttons in Pronterface behaves as if a G28 command without any variable has been issued and it homes all the axes. In the past, those buttons will home each axis independently. Issuing G28 X0 or G28 Y0 or G28 Z0 also behaves like a G28 as if Pronterface is not sending the parameter.