No, it doesn't work that way ... one IMenuManager is a model/renderer
for one SWT Menu. The contained IContributionItems map (more or less)
to each of the SWT MenuItems.
There's no generic way to clone the IContributionItems into a new
MenuManager.
Is it that you have a multi-instance view and you are adding some
actions/contribution items? Where in the code are you trying to add
them? Are you using getViewSite().getActionBars().getMenuManager()?