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/OptionsConfigurationBlock.java
private Shell fShell;
	public OptionsConfigurationBlock(IStatusChangeListener context, IJavaProject project) {
		fContext= context;
		fProject= project;
		
		fWorkingValues= getOptions(true);
		
		fCheckBoxes= new ArrayList();
		fComboBoxes= new ArrayList();
		fTextBoxes= new ArrayList(2); 
	}
	
	protected abstract String[] getAllKeys();
	
	protected Map getOptions(boolean inheritJavaCoreOptions) {
		if (fProject != null) {
			return fProject.getOptions(inheritJavaCoreOptions);
		} else {
			return JavaCore.getOptions();
		}	
	}
	
	protected Map getDefaultOptions() {
		return JavaCore.getDefaultOptions();
	}	
	
	public final boolean hasProjectSpecificOptions() {
		if (fProject != null) {
			Map settings= fProject.getOptions(false);
			String[] allKeys= getAllKeys();