Bug 120691 [Markers] Expanded categories not persisted between sessions
build I20051213 - in the Problems view in hierarchical mode, with many problems showing, - expand a few categories, select some leaf problems - shutdown / restart - the tree is collapsed Users will expect that the work they did to expand/collapse categories to see the problems they care most about will be persisted between sessions.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/markers/ExtendedMarkersView.java
setPrimarySortField(field, treeColumn);
				return;
			}
		}
		StatusManager.getManager().handle(
				StatusUtil.newStatus(IStatus.WARNING,
						"Sorting by non visible field " 
								+ field.getColumnHeaderText(), null));
	}
	/**
	 * Set the primary sort field to field and update the column.
	 * 
	 * @param field
	 * @param column
	 */
	private void setPrimarySortField(MarkerField field, TreeColumn column) {
		builder.setPrimarySortField(field);
		IWorkbenchSiteProgressService service = (IWorkbenchSiteProgressService) getViewSite()
				.getAdapter(IWorkbenchSiteProgressService.class);
		builder.refreshContents(service);
		updateDirectionIndicator(column, field);
		viewer.refresh();
	}
	/**
	 * Add group to the enabled filters.
	 * 
	 * @param group
	 */
	void toggleFilter(MarkerFieldFilterGroup group) {
		builder.toggleFilter(group);