Bug 127289 [Markers] SystemFilter and group selection state not preserved
We are not preserving the selection state of the system filters or which group is selected.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/views/markers/internal/MarkerView.java
.getCategories();
					if (categories != null) {
						for (int i = 0; i < categories.length; i++) {
							MarkerCategory category = categories[i];
							if (categoriesToExpand.contains(category.getName())) {
								getViewer().expandToLevel(category,
										AbstractTreeViewer.ALL_LEVELS);
							}
						}
					}
					categoriesToExpand.clear();
				}
			}
			return Status.OK_STATUS;
		}
		/**
		 * Add the category to the list of expanded categories.
		 * 
		 * @param category
		 */
		public void addExpandedCategory(MarkerCategory category) {
			categoriesToExpand.add(category.getName());
		}
		/**
		 * Remove the category from the list of expanded ones.
		 * 
		 * @param category
		 */
		public void removeExpandedCategory(MarkerCategory category) {
			categoriesToExpand.remove(category.getName());