static JSplitPane setSplitPaneOnFirstShowing(Component c, final value) {
  final JSplitPane sp = first(childrenOfType(c, JSplitPane.class));
  if (sp != null)
    onFirstResize(sp, r { 
      ifdef setSplitPaneOnFirstShowing_debug
        printVars setSplitPaneOnFirstShowing(+c, +value, size := c.getSize());
      endifdef
      sp.setDividerLocation(value);
    });
  ret sp;
}