We have our plugin/bundle marked in the Manifest as:
When in the Eclipse SDK and using Debug As | Eclipse Application, the
policy is observed and our plugin is not activated until the user selects
a contributed UI Part like a View.
When we do a PDE build and copy the plugin jar to the plugins directory
of a target stock Eclipse SDK and run that target Eclipse...the plugin's
Activator class is called every time. The Manifest is getting exported
during the build.