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
public static final String ID_CF_EDITOR=			"org.eclipse.jdt.ui.ClassFileEditor"; 
	
	/**
	 * The editor part id of the code snippet editor
	 * (value <code>"org.eclipse.jdt.ui.SnippetEditor"</code>).
	 */
	public static final String ID_SNIPPET_EDITOR= 		"org.eclipse.jdt.ui.SnippetEditor"; 
	/**
	 * The view part id of the Packages view
	 * (value <code>"org.eclipse.jdt.ui.PackageExplorer"</code>).
	 * <p>
	 * When this id is used to access
	 * a view part with <code>IWorkbenchPage.findView</code> or 
	 * <code>showView</code>, the returned <code>IViewPart</code>
	 * can be safely cast to an <code>IPackagesViewPart</code>.
	 * </p>
	 *
	 * @see IPackagesViewPart
	 * @see org.eclipse.ui.IWorkbenchPage#findView(java.lang.String)
	 * @see org.eclipse.ui.IWorkbenchPage#showView(java.lang.String)
	 */ 
	public static final String ID_PACKAGES= 			"org.eclipse.jdt.ui.PackageExplorer"; 
	
	/** 
	 * The view part id of the type hierarchy part.
	 * (value <code>"org.eclipse.jdt.ui.TypeHierarchy"</code>).
	 * <p>
	 * When this id is used to access
	 * a view part with <code>IWorkbenchPage.findView</code> or 
	 * <code>showView</code>, the returned <code>IViewPart</code>