|Employees typically use this strategy either when they are highly Machiavellian, or when their manager is a Mack truck. Look first at your managerial style. If you are a communicative, accessible, and responsive manager who truly treats employees with trust and respect, then you have a problem employee. If you are more in the unresponsive or over-controlling zone, then you have a problem.|
Assuming that you are a solid manager, you have an employee who is pretending to help you do your job, while his real goal is to help himself to your job. He may use the word, "suggestion," but his comments are actually criticism and public humiliation.
If this is the case, you should sit down with him and present the facts. Describe his specific unacceptable behaviors with examples and dates, let him know his actions are totally unacceptable, and then tell him they must stop.
However, if it is possible that he is engaging in this behavior because he has no other way to get his ideas and inputs across to you, then it may be time to refresh your management skills. Either way, your manager probably has a clear idea of your skills as well as those of your employee. If you have an open and communicative working relationship with your manager, you can discuss what is going on here. And if you do not have this type of relationship with him or her, then perhaps you have an even bigger problem.