For automatic scrolling, the only thing left to decide is how you want the ScrollBars to be displayed if the work
window dynamically grows or shrinks. There may be situations where the work window is the same size as or smaller
than the clip window. In this case, you may not want to display the ScrollBars, since they are not needed. If so, you
can set XmN-scrollBarDisplayPolicy to XmAS_NEEDED. If you always want the ScrollBars to be visible,
whether or not they are needed, you can set the resource to XmSTATIC. Some people prefer static ScrollBars, so that
consistency is maintained in the interface; having ScrollBars appear and disappear frequently may be confusing.
Perhaps the best thing to do is to allow the user to specify the XmNscrollBarDisplayPolicy. You can always
set your preference in the application defaults file, as shown below:
*XmScrolledWindow.scrollBarDisplayPolicy: static
10.2.2 Application−defined Scrolling
In the application−defined scrolling mode, XmNscrollingPolicy is set to XmAPPLICATION_DEFINED. In this
case, the work window must be the same size as the clip window, so the size of the work window is set by the toolkit.
As a result, the XmNvisualPolicy resource has the value of XmVARIABLE, which indicates that the work window
grows and shrinks with the ScrolledWindow. Since the two windows are the same size, the ScrolledWindow doesn't
need to have a clip window, so it doesn't create one.
Because application−defined scrolling implies that you are responsible for the creation ...