Total Validator Tool 

Performs four important validations on your web pages: True (X)HTML validation against published DTDs; accessibility validation against the W3C and US Section 508 guidelines; spell checking against one of five languages; and checking for broken links
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Xceed SmartUI for .NET 

Xceed SmartUI for .NET provides visual controls for easily creating user-friendly, state-of-the-art WinForms apps. Supports themed WinXP, Office XP and Office 2003 styles. Ten controls such as menubars, toolbars, treeviews and task panes.
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