Bug 21631 JavaUI.createTypeDialog() should provide default message [dialogs]
2.0 Release If you use JavaUI.createTypeDialog() to create a new (single selection) type dialog, and then open the dialog, the open will fail silently. The dialog cannot be succesfully opened unless you send setMessage() to the dialog before you open it. This behaviour should be documented, or, preferably, a default message ("Please select a type/class/interface") should be provided.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/ui/JavaUI.java
* (value <code>"org.eclipse.jdt.ui.CodingActionSet"</code>).
	 * 
	 * @since 2.0
	 */
	public static final String ID_CODING_ACTION_SET= "org.eclipse.jdt.ui.CodingActionSet"; 
	/**
	 * The id of the Java action set for open actions
	 * (value <code>"org.eclipse.jdt.ui.A_OpenActionSet"</code>).
	 * 
	 * @since 2.0
	 */
	public static final String ID_OPEN_ACTION_SET= "org.eclipse.jdt.ui.A_OpenActionSet"; 
	/**
	 * The id of the Java Search action set
	 * (value <code>org.eclipse.jdt.ui.SearchActionSet"</code>).
	 * 
	 * @since 2.0
	 */
	public static final String ID_SEARCH_ACTION_SET= "org.eclipse.jdt.ui.SearchActionSet"; 
	
	/**
	 * The editor part id of the editor that presents Java compilation units
	 * (value <code>"org.eclipse.jdt.ui.CompilationUnitEditor"</code>).
	 */	
	public static final String ID_CU_EDITOR=			"org.eclipse.jdt.ui.CompilationUnitEditor"; 
	
	/**
	 * The editor part id of the editor that presents Java binary class files
	 * (value <code>"org.eclipse.jdt.ui.ClassFileEditor"</code>).
	 */