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
group.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));
		group.setLayout(layout);
		String[] generateValues= new String[] { GENERATE, DO_NOT_GENERATE };
		label= PreferencesMessages.getString("CompilerConfigurationBlock.variable_attr.label"); 
		addCheckBox(group, label, PREF_LOCAL_VARIABLE_ATTR, generateValues, 0);
		
		label= PreferencesMessages.getString("CompilerConfigurationBlock.line_number_attr.label"); 
		addCheckBox(group, label, PREF_LINE_NUMBER_ATTR, generateValues, 0);		
		label= PreferencesMessages.getString("CompilerConfigurationBlock.source_file_attr.label"); 
		addCheckBox(group, label, PREF_SOURCE_FILE_ATTR, generateValues, 0);		
		label= PreferencesMessages.getString("CompilerConfigurationBlock.codegen_unused_local.label"); 
		addCheckBox(group, label, PREF_CODEGEN_UNUSED_LOCAL, new String[] { PRESERVE, OPTIMIZE_OUT }, 0);	
		
		return compComposite;
	}
		
	
	/* (non-javadoc)
	 * Update fields and validate.
	 * @param changedKey Key that changed, or null, if all changed.
	 */	
	protected void validateSettings(String changedKey, String newValue) {
		if (changedKey != null) {
			if (INTR_DEFAULT_COMPLIANCE.equals(changedKey)) {
				updateComplianceEnableState();
				if (DEFAULT.equals(newValue)) {
					updateComplianceDefaultSettings();
				}
				fComplianceStatus= validateCompliance();
			} else if (PREF_COMPLIANCE.equals(changedKey)) {