This blog post describes some guidelines for UI custom actions,
including one workaround.  The topics discussed have come up on this
mailing list on more than one occasion.

    UI Custom Action Guidelines
    <http://wp.me/pyVNs-gc>

    Windows Installer provides a rich set of standard actions that
    handle the typical needs of an installation: installing files and
    folders, manipulating the registry, searching for existing
    resources in the registry or the file system, controlling Windows
    services and so-on. Custom actions are handy things for when you
    need to do some custom processing that isn't covered by one of
    the standard actions. You can customize your UI experience by
    invoking an action when the user interacts with a control by
    publishing a DoAction control event for the control. This post
    describes some guidelines (and one workaround) for custom actions
    invoked by the user interface in a Windows Installer MSI package.

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"The Direct3D Graphics Pipeline" -- DirectX 9 draft available for download
 <http://legalizeadulthood.wordpress.com/the-direct3d-graphics-pipeline/>