I'm using VS 2008. I have SP1 and I'm using .NET 3.5.
I just started creating a new web project. I went to add calendar extender to a text box but noticed that little button with '>' was missing so I couldn't get to the add extender option. I then noticed the AJAX Control Toolkit tab was missing from the toolbox. I then manually added the AJAX Control Toolkit tab back and added the control back into the tab. After that I got the '>' button back and was able to add the calendar extender. However, it's not working right. When the calendar pops up it's about 1/2 below the text box instead of right underneath. Worse yet, if I open up the calendar control a second time the controls and stuff in it are all messed up and rearranged. Also, the content of the table cell the stuff is in disappears while the calendar is displayed.
I loaded up a previous project and everything seems to be working there. So this must be with new projects.