AJAX : Beware of following Controls in ASP.Net

The following ASP.NET controls are not compatible with partial-page updates, and are therefore not supported inside an UpdatePanel control:

• TreeView 
• Menu controls.
• FileUpload controls.
• GridView and DetailsView controls when their EnableSorting And Paging property is set to true.
• Login, PasswordRecovery, ChangePassword, and CreateUserWizard controls whose contents have not been converted to editable templates.
• Validation controls

• It includes the BaseCompareValidator, BaseValidator, CompareValidator, CustomValidator, RangeValidator, RegularExpressionValidator, RequiredFieldValidator, and ValidationSummary control. 

 Also i come to know that u cant do a partial update inside a repeter control.