Bug 49182 What should canceling setRawClasspath do ?
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/preferences/OptionsConfigurationBlock.java
return textBox;
	}	
	protected SelectionListener getSelectionListener() {
		if (fSelectionListener == null) {
			fSelectionListener= new SelectionListener() {
				public void widgetDefaultSelected(SelectionEvent e) {}
	
				public void widgetSelected(SelectionEvent e) {
					controlChanged(e.widget);
				}
			};
		}
		return fSelectionListener;
	}
	
	protected ModifyListener getTextModifyListener() {
		if (fTextModifyListener == null) {
			fTextModifyListener= new ModifyListener() {
				public void modifyText(ModifyEvent e) {
					textChanged((Text) e.widget);
				}
			};
		}
		return fTextModifyListener;
	}		
	
	protected void controlChanged(Widget widget) {
		ControlData data= (ControlData) widget.getData();
		String newValue= null;
		if (widget instanceof Button) {