A DrawingArea will usually be placed inside an container widget - a Form, a MainWindow, etc. and is frequently scrolled.
As such it usually inherits size and other resources from its parent widget.
You can set resources like XmNwidth and XmNheight for the DrawingArea.
The XmNresizePolicy may need to be set to allow changes in dimension in a program. Possible values are: XmRESIZE_ANY, XmRESIZE_GROW and XmRESIZE_NONE.
Three callbacks are associated with this widget: