[whpalmer4]

Send feedback to Omni. If enough other people express that opinion, they'll consider changing it, though part of the calculus will undoubtedly be to look at whether the proposed change will make it more or less likely that they'll get support contacts from confused users. The current behavior inconveniences some, but doesn't generate frustrated users reporting "I tried Duplicate but nothing shows up!" My guess is that the count of people who have actually complained about this implementation decision is pretty small, relatively speaking.

Or you could use AppleScript to implement something that would do the Duplicate operation despite being in Context mode. Such a script might look something like this:

tell application "OmniFocus"
	tell first document window of front document
		set selTrees to selected trees of content
		repeat with i from 1 to count of items of selTrees
			try
				set targetItem to value of item i of selTrees
				set newItem to duplicate targetItem to after targetItem
			on error
				display alert "Time to learn some AppleScript!"
			end try
		end repeat
	end tell
end tell

It would suffer from the same problems, such as duplicated items not appearing next to the original (if grouping by Added, for example) or at all (if duplicating a sequential action in a Next Action view).