Bug 329310 Part service does not autogenerate stacks if the last container is not one
bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/ui/internal/workbench/PartServiceImpl.java
} else if (child instanceof MPlaceholder) {
				MPlaceholder placeholder = (MPlaceholder) child;
				MUIElement ref = placeholder.getRef();
				if (ref == element) {
					return (MElementContainer<MUIElement>) container;
				} else if (ref instanceof MElementContainer<?>) {
					MElementContainer<MUIElement> match = findContainer((MElementContainer<?>) ref,
							element);
					if (match != null) {
						return match;
					}
				}
			} else if (child instanceof MElementContainer<?>) {
				MElementContainer<MUIElement> match = findContainer((MElementContainer<?>) child,
						element);
				if (match != null) {
					return match;
				}
			}
		}
		return null;
	}
	private MUIElement getRemoveTarget(MPart part) {
		MPlaceholder placeholder = getLocalPlaceholder(part);
		return placeholder == null ? part : placeholder;
	}
	private MPart showPart(PartState partState, MPart providedPart, MPart localPart) {
		MPart part = addPart(providedPart, localPart);
		switch (partState) {
		case ACTIVATE: