Bug 327964 EPartService's hidePart may fail when trying to hide a shared part that's in a shared container
The placeholder retrieval code in the EPartService implementation doesn't go far down deep enough and actually stops at the shared container level. This causes the placeholder of the shared part to not be found.
bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/ui/internal/workbench/PartServiceImpl.java
}
		}
		return container;
	}
	/**
	 * Returns the parent container of the specified element. If one cannot be found, a check will
	 * be performed to see whether the element is being represented by a placeholder, if it is, the
	 * placeholder's parent will be returned, if any.
	 * 
	 * @param element
	 *            the element to query
	 * @return the element's parent container, or the parent container of the specified element's
	 *         current placeholder, if it has one
	 */
	private MElementContainer<MUIElement> getParent(MUIElement element) {
		MElementContainer<MUIElement> parent = element.getParent();
		if (parent == null) {
			MPlaceholder placeholder = element.getCurSharedRef();
			if (placeholder == null) {
				MElementContainer<MUIElement> container = getContainer();
				return findContainer(container, element);
			}
			return placeholder.getParent();
		}
		return parent;
	}
	private MElementContainer<MUIElement> findContainer(MElementContainer<?> container,
			MUIElement element) {
		for (Object child : container.getChildren()) {
			if (child == element) {