Bug 328946 Part activation history may return incorrect candidate if no placeholders could be found in a perspective
1. Window > Open Perspective > Other... > CVS Repository Exploring 2. Hide the 'CVS Repositories' view. 3. The 'History' view should become active, it is not.
bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/ui/internal/workbench/PartActivationHistory.java
MUIElement selection = parent.getSelectedElement();
						if (selection == placeholder || selection == activePlaceholder
								|| selection == currentlyActivePart) {
							return candidate;
						}
					} else {
						return candidate;
					}
				}
			}
		}
		return null;
	}
	MPart getNextActivationCandidate(MPart part) {
		MArea area = isInArea(part);
		if (area != null) {
			
			MPart candidate = getSiblingActivationCandidate(part);
			if (candidate != null) {
				return candidate;
			}
			
			candidate = findActivationCandidate(
					modelService.findElements(area, null, MPart.class, null), part);
			if (candidate != null) {
				return candidate;
			}
		}
		
		MPart candidate = findActivationCandidate(generalActivationHistory, part);