I just downloaded version 4.1.7.429 of the Ajax toolkit and included into VS2010 Professional. When I use the DropShadowExtender, I get a strange result. If I set the Opacity to .5, or .25, or .75, the shadow is a lighter color and not the same color as the background. Any other setting of Opacity (as far as I've tested) is always the same as 1.0 which is basically black. set to .25 is a light gray shadow, .75 is a darker gray color, and .50 is a blue color. I've reinstalled the toolkit, used the ToolkitScriptManager and nothing changes. It also appears to have rounded edges even though Rounded is set to False. It is more noticable when width is larger.
Jim