Bug 87856 [Commands] Last closed editor leaked due to reference by command manager
bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/ParameterizedCommand.java
throw new NullPointerException(
					"A parameterized command cannot have a null command"); 
		}
		this.command = command;
		this.parameterizations = parameterizations;
	}
	public final int compareTo(final Object object) {
		final ParameterizedCommand command = (ParameterizedCommand) object;
		final boolean thisDefined = this.command.isDefined();
		final boolean otherDefined = command.command.isDefined();
		if (!thisDefined || !otherDefined) {
			return Util.compare(thisDefined, otherDefined);
		}
		try {
			return getName().compareTo(command.getName());
		} catch (final NotDefinedException e) {
			throw new Error(
					"Concurrent modification of a command's defined state"); 
		}
	}
	public final boolean equals(final Object object) {
		if (this == object) {
			return true;
		}
		if (!(object instanceof ParameterizedCommand)) {
			return false;
		}
		final ParameterizedCommand command = (ParameterizedCommand) object;
		if (!Util.equals(this.command, command.command)) {
			return false;