Bug 334559 EPartService's part searching path may not include parts outside of the active perspective
bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/ui/internal/workbench/PartServiceImpl.java
} else if (parent == null) {
			MPlaceholder placeholder = part.getCurSharedRef();
			if (placeholder != null) {
				parent = placeholder.getParent();
				if (parent instanceof MGenericStack) {
					recordSelectedActivation(parent);
				}
			}
		}
	}
	/**
	 * Records the specified parent 's selected element in the activation history.
	 * 
	 * @param parent
	 *            the element whose selected element should be checked for activation history
	 *            recording
	 */
	private void recordSelectedActivation(MElementContainer<? extends MUIElement> parent) {
		MUIElement selectedElement = parent.getSelectedElement();
		if (selectedElement instanceof MPart) {
			partActivationHistory.append((MPart) selectedElement);
		} else if (selectedElement instanceof MPlaceholder) {
			MUIElement ref = ((MPlaceholder) selectedElement).getRef();
			if (ref instanceof MPart) {
				partActivationHistory.append((MPart) ref);
			}
		}
	}
	/*
	 * (non-Javadoc)