Bug 214492 [Markers] Need to be able to add filters to existing markers views
Currently you can only add filters to a new markerContentProvider. We need to able to bind them to existing markerContentProviders as well.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/views/markers/internal/MarkerSupportRegistry.java
MarkerGroupingEntry entry = (MarkerGroupingEntry) objects[i];
				entry.getMarkerGroup().remove(entry);
				continue;
			}
			if (objects[i] instanceof AttributeMarkerGrouping) {
				AttributeMarkerGrouping entry = (AttributeMarkerGrouping) objects[i];
				entry.unmap();
				continue;
			}
			if (objects[i] instanceof String) {
				removeValues(objects[i], categories);
				continue;
			}
			if (objects[i] instanceof MarkerField) {
				fields.remove(((MarkerField) objects[i]).getId());
				continue;
			}
			if (objects[i] instanceof MarkerContentGenerator) {
				generators
						.remove(((MarkerContentGenerator) objects[i]).getId());
				continue;
			}
		}
	}
	/**
	 * Remove the value from all of the collection sets in cache. If the
	 * collection is empty remove the key as well.
	 * 
	 * @param value
	 * @param cache