Bug 327585 Commands, Handlers, and keybindings should use leaf lookup
bundles/org.eclipse.e4.core.commands/src/org/eclipse/e4/core/commands/internal/HandlerServiceImpl.java
* 
	 * @seeorg.eclipse.e4.core.commands.EHandlerService#executeHandler(org.eclipse.core.commands.
	 * ParameterizedCommand)
	 */
	public Object executeHandler(ParameterizedCommand command) {
		String commandId = command.getId();
		Object handler = lookUpHandler(context, commandId);
		if (handler == null) {
			return null;
		}
		try {
			addParmsToContext(command);
			Object rc = ContextInjectionFactory.invoke(handler, CanExecute.class, context,
					Boolean.TRUE);
			if (Boolean.FALSE.equals(rc))
				return null;
			return ContextInjectionFactory.invoke(handler, Execute.class, context, null);
		} finally {
			removeParmsFromContext(command);
		}
	}
	@Inject
	public void setContext(IEclipseContext c) {
		context = c;
	}
	public IEclipseContext getContext() {
		return context;
	}
}