Where can I find a Java package for handling MDI? There is nothing obvious in SWT. One reason I was thinking of having a WindowCommon class is that an application should have only one instance of the Display widget. It could go in a static initializer in WindowCommon. It seems to me that an abstract class combines the advantages of an ordinary class and an interface. The methods defined in that clas can be called from a class which extends it, and that class can also implement methods which are only declared as in an interface. With MDI the class hierarchy becomes something like WPManager, DocumentManager, Daisy and braille wondows. John -- John J. Boyer; President, Chief Software Developer Abilitiessoft, Inc. http://www.abilitiessoft.com Madison, Wisconsin USA Developing software for people with disabilities