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
Rectangle bounds = items[0].getBounds();
            Rectangle intersect = clientArea.intersection(bounds);
            if (intersect != null && intersect.height == bounds.height) {
                return new Point(Math.max(0, bounds.x
                        + getAvarageCharWith(tree) * CHAR_INDENT), bounds.y
                        + bounds.height);
            } else {
                return null;
            }
        default:
            Rectangle[] rectangles = new Rectangle[items.length];
            for (int i = 0; i < rectangles.length; i++) {
                rectangles[i] = items[i].getBounds();
            }
            Point cursorLocation = tree.getDisplay().getCursorLocation();
            Point result = findBestLocation(getIncludedPositions(rectangles,
                    clientArea), tree.toControl(cursorLocation));
            if (result != null) {
				result.x = result.x + getAvarageCharWith(tree) * CHAR_INDENT;
			}
            return result;
        }
    }
    /**
     * Hook to compute the menu location if the focus widget is
     * a table widget.
     * 
     * @param table the table widget that has the focus
     * 
     * @return a widget relative position of the menu to pop up or