Bug 273330 [JFace] Add API to MessageDialog to enable clients to use SWT.SHEET
A new style constant SWT.SHEET was added recently. Without adding new API in JFace, clients who are currently using the convenience methods MessageDialog.openWarning/Error/Information/Question/Confirmation would not be able to open these dialogs as sheets.
bundles/org.eclipse.jface/src/org/eclipse/jface/dialogs/MessageDialogWithToggle.java
*/
    private IPreferenceStore prefStore = null;
    /**
     * The toggle button (widget). This value is <code>null</code> until the
     * dialog is created.
     */
    private Button toggleButton = null;
    /**
     * The message displayed to the user, with the toggle button. This is the
     * text besides the toggle. If it is <code>null</code>, this means that
     * the default text for the toggle should be used.
     */
    private String toggleMessage;
    /**
     * The initial selected state of the toggle.
     */
    private boolean toggleState;
    /**
     * Creates a message dialog with a toggle. See the superclass constructor
     * for info on the other parameters.
     * 
     * @param parentShell
     *            the parent shell
     * @param dialogTitle
     *            the dialog title, or <code>null</code> if none
     * @param image
     *            the dialog title image, or <code>null</code> if none
     * @param message
     *            the dialog message
     * @param dialogImageType