There are certain items that are intially loaded from config files. I
believe there are also some 'hard coded' references that are loaded. The
rest of the assemblies are loaded when the first page using them is hit.
This is the case with third party controls.
If you want to reduce first hit with these controls, you can use the
precompile.axd "virtual" page to precompile the web application. It
essentially walks all of the pages to compile them. This is a 2.0 or later
feature, so it is not available in 1.x.

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Gregory A. Beamer
MVP, MCP: +I, SE, SD, DBA
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| Think outside the box!
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> When an ASP.NET Application first starts, an application pool is created
> and assemblies loaded into it.
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>
> Thanks.