Bug 264818 [Markers] Problems view: Status line shows wrong selection count summary
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/markers/ExtendedMarkersView.java
private Collection getCategoriesToExpand() {
		if (categoriesToExpand == null) {
			categoriesToExpand = new HashSet();
			if (this.memento != null) {
				IMemento expanded = this.memento.getChild(TAG_EXPANDED);
				if (expanded != null) {
					IMemento[] mementoCategories = expanded
							.getChildren(TAG_CATEGORY);
					MarkerCategory[] markerCategories = builder.getCategories();
					if (markerCategories != null) {
						for (int i = 0; i < markerCategories.length; i++) {
							for (int j = 0; j < mementoCategories.length; j++) {
								if (markerCategories[i].getName().equals(
										mementoCategories[j].getID()))
									categoriesToExpand.add(markerCategories[i]
											.getName());
							}
						}
					}
				}
			}
		}
		return categoriesToExpand;
	}
	/**
	 * Return the group used for categorisation.
	 * 
	 * @return MarkerGroup
	 */
	MarkerGroup getCategoryGroup() {