Bug 203838 [Markers] [Markers] clicking on column headers does not sort table
I20070918 Clicking on any of the column headers does not sort based on the relevant column.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/provisional/views/markers/CachedMarkerBuilder.java
if (event.getType() == IResourceChangeEvent.POST_BUILD) {
					scheduleMarkerUpdate();
					return;
				}
				
				if (progressService == null)
					markerProcessJob.schedule(TIME_OUT);
				else
					progressService.schedule(markerProcessJob, TIME_OUT);
			}
		};
	}
	/**
	 * Return the current list of markers.
	 * 
	 * @return MarkerMap
	 */
	public MarkerMap getVisibleMarkers() {
		if (currentMap == null) {
			scheduleMarkerUpdate();
			building = true;
		}
		if (building) {
			return MarkerMap.EMPTY_MAP;
		}
		return currentMap;
	}
	/**
	 * Return whether or not the receiver has markers without scheduling
	 * anything if it doesn't.