Please help: Keyboard short cut for 'add a linked shape' in OmniGraffle

I do a lot of process mapping. One joy of previous to 6 versions of OG was that I could select a shape and command click on the canvas and a duplicate shape would appear linked with a line to the original shape.
That don’t work any more. Which adds a ton of work for me.
I’ve asked this before with no reply. Please can someone help me do this?
Thanks in anticipation