Client Validators not working in Firefox & Menu Control with master pages not working

If you upgraded a .NET 1.x project to 2.0 and now have issues with Client Validators not functioning in Firefox (they work server side) or the menu control is displaying the menu items all over the place when used with master pages, then try this tip. In the Web.Config, if there is the tag:

then remove it - it is the root of all evil - unless you plan to use IE 3!
One interesting thing to note - removing it changes all of the client side id's to .NET 2's new way of doing things, so if you have written some javascript into your pages - changes may be required.