Bug 80429 [Preferences] [Dialogs] FieldEditors should relax requirements to support DialogPages
bundles/org.eclipse.jface/src/org/eclipse/jface/preference/FieldEditor.java
* both this method and <code>isValid</code>.
     * </p>
     *
     * @see #isValid
     */
    protected void refreshValidState() {
    }
    /**
     * Sets the focus to this field editor.
     * <p>
     * The default implementation of this framework method
     * does nothing. Subclasses may reimplement.
     * </p>
     */
    public void setFocus() {
        
    }
    /**
     * Sets this field editor's label text.
     * The label is typically presented to the left of the entry field.
     *
     * @param text the label text
     */
    public void setLabelText(String text) {
        Assert.isNotNull(text);
        labelText = text;
        if (label != null)
            label.setText(text);
    }
    /**