in the manual it says that I can option-Click a marker to have the info pane display the duration.
However, when i option click that marker, absolutely nothing happens i.e. no information is to find in the information pane.
Yes... I HAVE more than one marker in the timeline
Again, layer markers and you need to click at least two in sequence to see any duration. Comp markers and a single markers only display their absolute time in the comp.