Bug 214137 [Markers] Unbound system filters should be bound to problems view.
In 3.3 we supported systemFilters which are not currently picked up by the problems view. We should pick these up for compatiblity.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/markers/CachedMarkerBuilder.java
* @param marker
	 * @return MarkerItem or <code>null<code> if it cannot be found
	 */
	MarkerItem getMarkerItem(IMarker marker) {
		if (refreshingMarkers())
			return null;
		return currentMap.getMarkerItem(marker);
	}
	/**
	 * Get the name for the preferences for the receiver.
	 * 
	 * @return String
	 */
	private String getMementoPreferenceName() {
		return getClass().getName() + viewId;
	}
	/**
	 * Return the primary sort field
	 * 
	 * @return MarkerField
	 */
	MarkerField getPrimarySortField() {
		return getComparator().getPrimarySortField();
	}
	/**
	 * Get the sort direction of field
	 * 
	 * @param field
	 * @return int one of {@link MarkerComparator#ASCENDING} or
	 *         {@link MarkerComparator#DESCENDING}