Bug 30751 [Viewers] Closing all projects doesnt clear package browser list [browsing]
In the java browsing perspective, if you close all projects, the packages browser still has a list of all the packages from the last opened project.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/StructuredViewer.java
* Adds the given filter to this viewer,
 * and triggers refiltering and resorting of the elements.
 *
 * @param filter a viewer filter
 */
public void addFilter(ViewerFilter filter) {
	if (filters == null)
		filters = new ArrayList();
	filters.add(filter);
	refresh();
}
/**
 * Associates the given element with the given widget.
 * Sets the given item's data to be the element, and maps
 * the element to the item in the element map (if enabled).
 *
 * @param element the element
 * @param item the widget
 */
protected void associate(Object element, Item item) {
	Object data = item.getData();
	if (data != element) {
		if (data != null)
			disassociate(item);
		item.setData(element);
	}
	
	
	
	mapElement(element, item);