Package not appearing on Prerequisites dialog?

I was helping someone create a custom Bootstrapper package last week and after copying

their package files into the Bootstrapper\Packages folder, it did not appear on the prerequisites dialog.  I told them it would probably be one of two things:

Product.xml or Package.xml file is invalid

If the XML doesn’t match the Bootstrapper schema, it will not be loaded into the prerequisites dialog.  You can verify they are valid by simply opening the package manifests in Visual Studio, it will load the appropriate schema and give you line squigglies as nessecary.

Restart Visual Studio (for ClickOnce projects)

If you open the Prerequisites dialog from a Setup Project, it loads all the bootstrapper packages on disk and populates the dialog.  For ClickOnce projects (.Net Windows applications) however, this is only done once and the results are cached.

If you put your package into the Bootstrapper\Packages folder after you have loaded the Prerequisites dialog it won’t be selectable until you restart devenv.exe.