Bug 270008 [CommonNavigator] Ability to extend bindings beyond "inheritsBindingsFrom" tag
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/extensions/Binding.java
*/
	boolean isVisibleExtension(String anExtensionId) {
		
		
		if (knownIds.containsKey(anExtensionId)) {
			
			return ((Boolean) knownIds.get(anExtensionId)).booleanValue();
		}
		
		for (Iterator itr = includePatterns.iterator(); itr.hasNext();) {
			Pattern pattern = (Pattern) itr.next();
			if (pattern.matcher(anExtensionId).matches()) {
				
				knownIds.put(anExtensionId, Boolean.TRUE);
				if (Policy.DEBUG_RESOLUTION) {
					System.out.println("Viewer Binding: " + TAG_EXTENSION +
							" to: " + anExtensionId); 
				}
				return true;
			}
		}
		for (Iterator itr = excludePatterns.iterator(); itr.hasNext();) {
			Pattern pattern = (Pattern) itr.next();
			if (pattern.matcher(anExtensionId).matches()) {
				knownIds.put(anExtensionId, Boolean.FALSE);
				if (Policy.DEBUG_RESOLUTION) {
					System.out.println("Viewer Binding: EXCLUDED: " + TAG_EXTENSION +
							" to: " + anExtensionId); 
				}
				return false;