Platform UI MarkersView
The pre 3.4 implementation of a view for Tasks, Bookmarks and Problems is not sufficient for how many people are using markers. See the org.eclipse.ui.ide.markerSupport schema for full details.
In 3.4 the MarkerSupportView was added to allow clients to create thier own markers views more suited to thier applications. A MarkerSupportView is created by referring to the markerContentGenerator.