Bug 155273 [Markers] Visibility of problems view columns should be configurable
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/markers/CachedMarkerBuilder.java
int length = 0;
		for (int i = 0; i < elements.length; i++) {
			length += elements[i].getChildren().length;
		}
		return length;
	}
	/**
	 * Return the resource listener for the builder
	 * 
	 * @return IResourceChangeListener
	 */
	private IResourceChangeListener getUpdateListener() {
		return new IResourceChangeListener() {
			/**
			 * Returns whether or not the given even contains marker deltas for
			 * this view.
			 * 
			 * @param event
			 *            the resource change event
			 * @return <code>true</code> if the event contains at least one
			 *         relevant marker delta
			 * @since 3.3
			 */
			private boolean hasMarkerDelta(IResourceChangeEvent event) {
				Iterator markerTypes = generator.getMarkerTypes().iterator();
				while (markerTypes.hasNext()) {
					MarkerType type = (MarkerType) markerTypes.next();
					if (event.findMarkerDeltas(type.getId(), true).length > 0)
						return true;
				}