Bug 329930 Resetting a perspective while its active part is not defined in the perspective causes the perspective to not have an active part after the reset
1. Window > Show View > Console 2. Window > Reset Perspective... > OK 3. No parts are active.
bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/ui/workbench/modeling/EPartService.java
/**
	 * Applicable states that a part can be in. This will be used in conjunction with
	 * {@link EPartService#showPart(String, PartState)}.
	 */
	public enum PartState {
		/**
		 * Part state that indicates the part should be made visible and activated.
		 */
		ACTIVATE,
		/**
		 * Part state that indicates the part should be made visible though it may not necessarily
		 * be granted focus. If the part will be displayed in the same stack as the currently active
		 * part, then this has the same effect as <code>ACTIVATE</code>.
		 */
		VISIBLE,
		/**
		 * Part state that indicates the part should be created but not necessarily made visible.
		 */
		CREATE
	}