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
categoriesToExpand.add(next.getParent());
				} else
					categoriesToExpand.add(next);
			}
		}
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.ui.part.ViewPart#saveState(org.eclipse.ui.IMemento)
	 */
	public void saveState(IMemento memento) {
		super.saveState(memento);
		memento.putString(TAG_GENERATOR, builder.getGenerator().getId());
		builder.saveState(memento);
	}
	/**
	 * Select all of the elements in the receiver.
	 */
	void selectAll() {
		viewer.getTree().selectAll();
	}
	/**
	 * Set the category group for the receiver.
	 * 
	 * @param group
	 */
	void setCategoryGroup(MarkerGroup group) {
		categoriesToExpand.clear();
		builder.setCategoryGroup(group);