XmMainWindowSep1 returns the widget ID of the first Separator
in the MainWindow.
The first Separator is located between the MenuBar and the Command widget.
This Separator is visible only when XmNshowSeparator is True.
NOTE: XmMainWindowSep1 is obsolete and exists for compatibility
with previous releases. Use XtNameToWidget instead. Pass
a MainWindow variable as the first argument to XtNameToWidget
and pass Separator1 as the second argument.
For a complete definition of MainWindow and its associated resources, see
Specifies the MainWindow widget ID