Bug 33550 [Dialogs] Dialog should support remembering size and position
There are several dialogs that remember its size and position. Since restore the size and considering screen size and font changes isn't trivial JFace's Dialog class should support remembering and restoring size and position. These would realy ease the task for subclasses. May be you can steel the code from OpenTypeSelectionDialog.
bundles/org.eclipse.jface/src/org/eclipse/jface/dialogs/Dialog.java
* @since 2.0
     */
    public static final String DLG_IMG_MESSAGE_WARNING = "dialog_messasge_warning_image"; 
    /**
     * Image registry key for info message image (value
     * <code>"dialog_message_error_image"</code>).
     * 
     * @since 2.0
     */
    public static final String DLG_IMG_MESSAGE_ERROR = "dialog_message_error_image"; 
    /**
     * The ellipsis is the string that is used to represent shortened
     * text.
     * @since 3.0
     */
    public static final String ELLIPSIS = "..."; 
    /**
     * NOTE: Dialog does not the following images in the registry
     * 	 	DLG_IMG_ERROR
     * 		DLG_IMG_INFO
     * 		DLG_IMG_QUESTION
     * 		DLG_IMG_WARNING
     * 
     * They are now coming directly from SWT see ImageRegistry.  For backwards 
     * compatibility they are still supported, however new code should use SWT
     * for these.
     * 
     * @see Display#getSystemIcon(int ID)
     */
    static {