Case: Create a full-screen event calendar that displays the events as a hyperlink, and displays the description of the event when the mouse hovers over the event link.
Issue: ASP.NET 2.0’s Calendar control displays a tooltip "Calendar" or "Databound Calendar" when the mouse hovers over the control. Even if you set the Tooltip property to an empty string.
Resolution: This has to do with the title attribute that asp.net sticks in there. In the Page_Load event add the following:
Alternatively you can set the UseAccessibleHeader property of the control to false, but then screen readers would have a difficult time dealing with this.