This can be caused by having custom JavaScript in the HTML content of the TeamRaiser page you are trying to edit. When clicking the Edit buttons in the Event Management Center on the Event Web Site tab, it is running JavaScript to cause the edit menu to pop up. If there is already customized code in the TeamRaiser page that you are trying to edit, it can potentially cause a conflict between the two JavaScripts trying to run at the same time if not written properly, thus resulting in a glitch.

To verify this, open the Java Console before attempting to edit a page and check to see if errors occur when clicking the edit button.  If this is happening, the Javascript in the TeamRaiser page must either be removed or edited to correctly work in the Event Manager Console.