Bug 208101 [Markers] Tasks content has mark completed enabled for non editable tasks
I20071030-0100 Mark completed is enabled for tasks that are not editable
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/provisional/views/markers/ExtendedMarkersView.java
addAllConcreteItems(elements[i], allMarkers);
		}
		MarkerItem[] markers = new MarkerItem[allMarkers.size()];
		allMarkers.toArray(markers);
		return markers;
	}
	/**
	 * Add all concrete {@link MarkerItem} elements associated with the receiver
	 * to allMarkers.
	 * 
	 * @param markerItem
	 * @param allMarkers
	 */
	private void addAllConcreteItems(MarkerItem markerItem,
			Collection allMarkers) {
		if (markerItem.isConcrete()) {
			allMarkers.add(markerItem);
			return;
		}
		
		MarkerItem[] children = markerItem.getChildren();
		for (int i = 0; i < children.length; i++) {
			addAllConcreteItems(children[i], allMarkers);
		}
	}
	/**
	 * Return the group used for categorisation.
	 * 
	 * @return MarkerGroup
	 */