I went to the Code Plex site and down load the latest toolkit. Then followed the instructions on how to set up the toolkit to the letter. When I first loaded the toolkit everything worked. But now every time I start up my computer and start VS all the AJAX controls I have on any page has the green squiggly line underneath it and the error says:
Element <AJAX Control Name> is not a known element. This can occur if there is a compilation error in the web site, or the webconfig file is missing.
The only thing I can do is delete the Ajax Toolkit tab then add the tab again and then "Choose Items..." and load the Ajax controls again. Then I have to add an AJAX control from the toolkit to any webpage. Once that is done all the green squiggly lines go away and I can continue.