Bug 24521 [Viewers] TreeViewer.update() does not work correctly with filter
When I add an element which does not satisfy the filtering condition and then update it so that it does, call to update does not show the element. This is because[StructuredViewer.update]: public void update(Object element, String[] properties) { Assert.isNotNull(element); | Widget item = findItem(element); | if (item == null) | return; the code silently ignores that the element may become visible... btw. later in code of this method: if (needsRefilter) { refresh(); return; } This is quite inefficient, as it needs to query all visible items; however only one element may actually change (change visibility and/or sort order).
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/StructuredViewer.java
* Removes the given association from the internal element to widget map.
	 * Does nothing if mapping is disabled, or if the given element does not map
	 * to the given item.
	 * <p>
	 * This method is internal to the framework; subclassers should not call
	 * this method.
	 * </p>
	 * 
	 * @param element
	 *            the element
	 * @param item the item to unmap
	 * @since 2.0
	 */
	protected void unmapElement(Object element, Widget item) {
		
		
		if (elementMap != null) {
			Object widgetOrWidgets = elementMap.get(element);
			if (widgetOrWidgets == null) {
				
				return;
			} else if (widgetOrWidgets instanceof Widget) {
				if (item == widgetOrWidgets) {
					elementMap.remove(element);
				}
			} else {
				Widget[] widgets = (Widget[]) widgetOrWidgets;
				int indexOfItem = Arrays.asList(widgets).indexOf(item);
				if (indexOfItem == -1) {
					return;