Bug 163281 FieldEditorPreferencePage needs a default constructor
bundles/org.eclipse.jface/src/org/eclipse/jface/preference/FieldEditorPreferencePage.java
* Layout constant (value <code>1</code>) indicating that
     * the field editors' basic controls are put into a grid layout.
     */
    public static final int GRID = 1;
    /** 
     * The vertical spacing used by layout styles <code>FLAT</code> 
     * and <code>GRID</code>.
     */
    protected static final int VERTICAL_SPACING = 10;
    /** 
     * The margin width used by layout styles <code>FLAT</code> 
     * and <code>GRID</code>.
     */
    protected static final int MARGIN_WIDTH = 0;
    /** 
     * The margin height used by layout styles <code>FLAT</code> 
     * and <code>GRID</code>.
     */
    protected static final int MARGIN_HEIGHT = 0;
    /**
     * The field editors, or <code>null</code> if not created yet.
     */
    private List fields = null;
    /**
     * The layout style; either <code>FLAT</code> or <code>GRID</code>.
     */
    private int style;
    /** 
     * The first invalid field editor, or <code>null</code>
     * if all field editors are valid.