>I drop the _webbrowser41 class in my form to show up an html page. The problem is that I want to disable the righclick event inside this class. I'm running this in a citrix server and through the view source option inside the rightclick menu the user can access the server folders (file,open)

This is not a VFP thing, it is an Internet Explorer issue since IE has control when the mouse is over the webbrowser control. The only way to disable the rightmouse click on a page hosting the control is within script code of the page being rendered, so you may not be able to do what you are trying to do here.