Bug 325836 EPartService's createSharedPart(*) methods should not need its MWindow parameter
The service should only be interacting with its own window and not some other random window.
bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/ui/internal/workbench/PartServiceImpl.java
((MPlaceholder) element).getRef().setCurSharedRef((MPlaceholder) element);
			element = ((MPlaceholder) element).getRef();
		}
		return element instanceof MPart ? (MPart) element : null;
	}
	public Collection<MPart> getParts() {
		return modelService.findElements(getContainer(), null, MPart.class, null);
	}
	public boolean isPartVisible(MPart part) {
		if (isInContainer(part)) {
			MUIElement element = part;
			MElementContainer<?> parent = part.getParent();
			if (parent == null) {
				
				element = part.getCurSharedRef();
				if (element == null) {
					return false;
				}
				parent = element.getParent();
				if (parent == null) {
					return false;
				}
			}
			if (parent instanceof MPartStack) {
				return parent.getSelectedElement() == element;
			}
			return element.isVisible();
		}
		return false;
	}