Bug 157072 [ActionSets][Contributions] QuickMenuAction funtionality should be made public
The QuickMenuAction class should be made public and usable by IWorkbenchWindowPulldownDelegate{2}. As it is you need to roll this functionality yourself in the run method of your delegate (and it is by no means straightforward).
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/actions/QuickMenuAction.java
result = computeMenuLocation(styledText);
        } else if (focus instanceof Tree) {
            Tree tree = (Tree) focus;
            clientArea = tree.getClientArea();
            result = computeMenuLocation(tree);
        } else if (focus instanceof Table) {
            Table table = (Table) focus;
            clientArea = table.getClientArea();
            result = computeMenuLocation(table);
        }
        if (result == null) {
            result = focus.toControl(cursorLocation);
        }
        if (clientArea != null && !clientArea.contains(result)) {
            result = new Point(clientArea.x + clientArea.width / 2,
                    clientArea.y + clientArea.height / 2);
        }
        Rectangle shellArea = focus.getShell().getClientArea();
        if (!shellArea.contains(focus.getShell().toControl(
                focus.toDisplay(result)))) {
            result = new Point(shellArea.x + shellArea.width / 2, shellArea.y
                    + shellArea.height / 2);
        }
        return focus.toDisplay(result);
    }
    /**
     * Hook to compute the menu location if the focus widget is
     * a styled text widget.
     * 
     * @param text the styled text widget that has the focus