HelpStudio 

Generate help output in cross-platform plain HTML, HTML Help, Help 2.0 or printable PDF. HelpStudio seamlessly combines a feature packed WYSIWYG authoring environment with HTML based layout templates.
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Document! X 

Document! X automates the process of creating and maintaining documentation for a wide range of solution elements: VB.NET/C#/C++ .NET Projects; VB 5 or 6 / VBA Projects; Compiled COM Components and Controls; COM Type Libs, Databases, XSD Schemas.
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DC Help Authority 

Help Authority that allows you to assign a sensitive help for every control in within your form or even every column in your grid
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