Bug 322403 Showing a shared part with PartState.VISIBLE may not work correctly due to incorrect parent comparisons
We check the parents of the active part against the part-to-be-shown to determine how to respond when PartState.VISIBLE is used but the check is always 'true' for shared parts because getParent() returns 'null' for both parts. This is obviously wrong. We need to update the code to consider placeholders.
bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/ui/internal/workbench/PartServiceImpl.java
}
		part.setCloseable(descriptor.isCloseable());
		part.setContributionURI(descriptor.getContributionURI());
		part.setLabel(descriptor.getLabel());
		part.setIconURI(descriptor.getIconURI());
		part.setTooltip(descriptor.getTooltip());
		part.getHandlers().addAll(EcoreUtil.copyAll(descriptor.getHandlers()));
		part.getTags().addAll(descriptor.getTags());
		part.getBindingContexts().addAll(descriptor.getBindingContexts());
		return part;
	}
	public MPart createPart(String id) {
		MPartDescriptor descriptor = findDescriptor(id);
		return createPart(descriptor);
	}
	public MPlaceholder createSharedPart(String id, MWindow sharedWindow) {
		return createSharedPart(id, sharedWindow, false);
	}
	public MPlaceholder createSharedPart(String id, MWindow sharedWindow, boolean force) {
		
		MPart sharedPart = null;
		
		if (!force) {
			for (MUIElement element : sharedWindow.getSharedElements()) {
				if (element.getElementId().equals(id)) {
					sharedPart = (MPart) element;
					break;
				}
			}
		}