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
public String getValue(boolean selection) {
			int index= selection ? 0 : 1;
			return fValues[index];
		}
		
		public String getValue(int index) {
			return fValues[index];
		}		
		
		public int getSelection(String value) {
			for (int i= 0; i < fValues.length; i++) {
				if (value.equals(fValues[i])) {
					return i;
				}
			}
			throw new IllegalArgumentException();
		}
	}
	
	
	protected Map fWorkingValues;
	protected ArrayList fCheckBoxes;
	protected ArrayList fComboBoxes;
	protected ArrayList fTextBoxes;
	
	private SelectionListener fSelectionListener;
	private ModifyListener fTextModifyListener;
	protected IStatusChangeListener fContext;
	protected IJavaProject fProject;