Bug 205049 Other plug-ins should be able to define default content generator
Currently only the content generator can define which plug-ins it can be the default for - we need a way for plug-ins to refer back to the marker support for thier own generator.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/views/markers/internal/MarkerSupportRegistry.java
processContentGenerator(tracker, extension, element);
				continue;
			}
			if (element.getName().equals(MARKER_FIELD)) {
				processMarkerField(tracker, extension, element);
				continue;
			}
		}
	}
	/**
	 * Create a table of MarkerFields
	 * 
	 * @param tracker
	 * @param extension
	 * @param element
	 */
	private void processMarkerField(IExtensionTracker tracker,
			IExtension extension, IConfigurationElement element) {
		MarkerField field = null;
		try {
			field = (MarkerField) IDEWorkbenchPlugin.createExtension(element,
					ATTRIBUTE_CLASS);
			field.setConfigurationElement(element);
		} catch (CoreException e) {
			StatusManager.getManager().handle(e.getStatus());
		}
		if (field != null)
			fields.put(element
					.getAttribute(MarkerSupportConstants.ATTRIBUTE_ID), field);
	}