From Learn About the Ext JavaScript Library

Types of Dialogs

• BasicDialog (doc) - Lightweight Dialog Class
• MessageBox (doc) - Utility class for generating different styles of message boxes
• LayoutDialog (doc) - Dialog which provides adjustments for working with a layout in a Dialog

Ext 2.x

• BasicDialog and LayoutDialog have been deprecated.
• Ext Migration Guide #Upgrading Layouts to Windows - Ext 1 to 2 Migration Guide