Connectivity Cockpit: show edges from selection is no longer working

What is the button "show edges in selection" expected to do ?
Should it show all edges starting in the current selection ?
Only edges within the selected nodes ?

It doesn't seem to do any of the above.
E.g. try defining "left hemisphere" and "right hemisphere" selections and then press "Selected Show". It works only for one of the hemispheres in my situation.