unable to drag and drop modalpopupextender ajax control

I am new to Ajax and installed and can see the toolkit 开发者_C百科controls.

Now I am trying to drag and drop the modalpopupextender on my page, put I get a cross sign meaning that I can't drop it on the page.

Any ideas appreciated.

Thanks

This question has been asked before if you search in Google.

Some advice:

1. Reset your referrences from tools->choosetoolbox items in VS
2. Put your dll in bin foler of your project, THEN do the whole AJAX set-up. Don't put the dll on your desktop as the referrence will always point to the desktop and if it is deleted then problem
3. Make sure
4. First put the Toolkitcontrol on the page
5. Then if you are still unable to drag and drop onto the page like me, drag and drop into the source view