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 true;
				}
			} else if (object instanceof MWindow) {
				MWindow win = (MWindow) object;
				for (MWindow dw : win.getWindows()) {
					if (isInContainer(dw, element))
						return true;
				}
			}
		}
		if (container instanceof MWindow) {
			MWindow win = (MWindow) container;
			for (MWindow dw : win.getWindows()) {
				if (isInContainer(dw, element))
					return true;
			}
		}
		if (container instanceof MPerspective) {
			MPerspective persp = (MPerspective) container;
			for (MWindow dw : persp.getWindows()) {
				if (isInContainer(dw, element))
					return true;
			}
		}
		return false;
	}
	private MPlaceholder getLocalPlaceholder(MPart part) {
		return getLocalPlaceholder(getContainer(), part);
	}
	private MPlaceholder getLocalPlaceholder(MElementContainer<?> container, MPart part) {