Progress
Programming
Handbook


Widget Realization

When you create or define a widget, Progress creates an internal data structure associated with that widget. Before the widget can be displayed on the screen, the window system must also create a data structure for the widget. When this second data structure exists, the widget is realized.

You can modify some widget attributes at any time. Other attributes are initially modifiable, but become fixed while the widget is realized. This means that you cannot modify these attributes again unless the widget is derealized. A widget becomes derealized when the associated data structure within the windowing system is deleted.

There are two reasons it is important for you to understand when realization and derealization occur. First, because you cannot change some attributes while the widget is realized and, second, because some attributes must be set to a valid value before realization takes place.


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