Bug 294303 [Markers] 'Queuing Viewer Updates' in Problems view
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/markers/ExtendedMarkersView.java
for (Iterator i = structuredSelection.iterator(); i.hasNext();) {
			Object next = i.next();
			if (next instanceof IMarker) {
				MarkerItem marker = builder.getMarkers().getMarkerItem(
						(IMarker) next);
				if (marker != null) {
					newSelection.add(marker);
				}
			}
		}
		IStructuredSelection structured = new StructuredSelection(newSelection);
		viewer.setSelection(structured, reveal);
		updateStatusLine(structured);
	}
	/**
	 * Add group to the enabled filters.
	 * 
	 * @param group
	 */
	void toggleFilter(MarkerFieldFilterGroup group) {
		generator.toggleFilter(group);
	}
	/**
	 * Toggle the sort direction of the primary field
	 */
	void toggleSortDirection() {
		setPrimarySortField(builder.getPrimarySortField());
	}
	/**
	 * Update the direction indicator as column is now the primary column.