Bug 327980 Part activation history should not be perspective-dependent
bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/ui/internal/workbench/PartActivationHistory.java
MPlaceholder placeholder = part.getCurSharedRef();
						if (placeholder == null || !placeholder.isToBeRendered()
								|| !isValid(placeholder.getParent())) {
							it.remove();
							continue;
						} else if (!placeholder.isVisible()) {
							continue;
						}
						return part;
					} else if (isValid(parent)) {
						return part;
					}
				}
			}
		}
		candidates = perspective.getContext().get(EPartService.class).getParts();
		for (MPart candidate : candidates) {
			if (isValid(perspective, candidate)) {
				return candidate;
			}
		}
		return null;
	}
	private MPart getSiblingActivationCandidate(MPart part, MUIElement element,
			Collection<MPart> activationHistory) {
		List<MUIElement> siblings = element.getParent().getChildren();
		for (MPart previouslyActivatedPart : activationHistory) {
			if (previouslyActivatedPart != part && previouslyActivatedPart.isToBeRendered()) {
				if (siblings.contains(previouslyActivatedPart)) {
					return previouslyActivatedPart;