Select 2 objects
RMB ->Measure distance between objects
A message report window will pop-up
This will report:
A Minimum distance
B Minimum center-center distance
C Minimum distance X,Y
D Minimum center-center distance X,Y
If one of the selections contain more then 1 object, the distance can not be calculated.
A message: 2 objects should be selected will appear.
To unselect a object when 2 objects where selected at the same coordinate use: RMB-> Unselect first object
Refresh the screen with F5 and measure the distance according step 3.