Bug 251517 [Preferences] Increase visibility for the ListEditor fields or methods
Build ID: M20080911-1700 Steps To Reproduce: I am trying to create a specialized org.eclipse.jface.preference.ListEditor. I want to specialize the 'remove' button so that I can disable it in a case where it we shouldn't allow them to remove the entry. However, currently all methods and fields that provide access to the buttons or event handling are all private, and thus can not be overridden by subclasses. Expected result is that protected access is provided for dealing with selection changes, button presses, and protected access is provided for access to the buttons so we can enable/disable them as needed. More information:
bundles/org.eclipse.jface/src/org/eclipse/jface/preference/ListEditor.java
* Creates a list field editor.
     * 
     * @param name the name of the preference this field editor works on
     * @param labelText the label text of the field editor
     * @param parent the parent of the field editor's control
     */
    protected ListEditor(String name, String labelText, Composite parent) {
        init(name, labelText);
        createControl(parent);
    }
    /**
     * Notifies that the Add button has been pressed.
     */
    private void addPressed() {
        setPresentsDefaultValue(false);
        String input = getNewInputObject();
        if (input != null) {
            int index = list.getSelectionIndex();
            if (index >= 0) {
				list.add(input, index + 1);
			} else {
				list.add(input, 0);
			}
            selectionChanged();
        }
    }
    /* (non-Javadoc)
     * Method declared on FieldEditor.
     */
    protected void adjustForNumColumns(int numColumns) {