Bug 40300 Compiler pref page does not disable unavailable preferences [build path]
I20030716 + plug-in export If I set a parent preference to ignore I'd expect that sub-properties get disabled.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/preferences/CompilerConfigurationBlock.java
private static final String ERROR= JavaCore.ERROR;
	private static final String WARNING= JavaCore.WARNING;
	private static final String IGNORE= JavaCore.IGNORE;
	private static final String ABORT= JavaCore.ABORT;
	
	private static final String CLEAN= JavaCore.CLEAN;
	private static final String ENABLED= JavaCore.ENABLED;
	private static final String DISABLED= JavaCore.DISABLED;
		
	private static final String DEFAULT= "default"; 
	private static final String USER= "user";	 
	private ArrayList fComplianceControls;
	private PixelConverter fPixelConverter;
	private IStatus fComplianceStatus, fMaxNumberProblemsStatus, fResourceFilterStatus;
	public CompilerConfigurationBlock(IStatusChangeListener context, IJavaProject project) {
		super(context, project);
		
		fComplianceControls= new ArrayList();
			
		fComplianceStatus= new StatusInfo();
		fMaxNumberProblemsStatus= new StatusInfo();
		fResourceFilterStatus= new StatusInfo();
	}
	
	private final String[] KEYS= new String[] {
		PREF_LOCAL_VARIABLE_ATTR, PREF_LINE_NUMBER_ATTR, PREF_SOURCE_FILE_ATTR, PREF_CODEGEN_UNUSED_LOCAL,
		PREF_CODEGEN_TARGET_PLATFORM, PREF_PB_OVERRIDING_PACKAGE_DEFAULT_METHOD,
		PREF_PB_METHOD_WITH_CONSTRUCTOR_NAME, PREF_PB_DEPRECATION, PREF_PB_HIDDEN_CATCH_BLOCK, PREF_PB_UNUSED_LOCAL,
		PREF_PB_UNUSED_PARAMETER, PREF_PB_SYNTHETIC_ACCESS_EMULATION, PREF_PB_NON_EXTERNALIZED_STRINGS,