Controls/Events within foriegn app

Programming language used: VB.net

Problem: I am trying to get a tooltip to appear over a form to a closed source app. Based on the location within the form there must be a way to accomplish this. I would also like to be able to monitor click events within the boundaries of the form or display controls over the form. All of this must be initialized when the form is opened (event within Windows object model??). Please be decently thorough. Thanks.