// also works when using centering of the component,
// e.g. through jscroll_center_borderless
svoid onEnclosingScrollPaneResize(JComponent c, Runnable r) {
  if (r == null) ret;
  new Var<> listener;
  bindToComponent(c, -> {
    var viewport = getParent(getParent(c));
    if (viewport instanceof JViewPort) {
      listener.set(new ComponentAdapter {
        public void componentResized(ComponentEvent e) {
          pcallF(r);
        }
      });
      c.addComponentListener(listener!);
    }
  }, -> {
    if (listener.has()) {
      var viewport = getParent(getParent(c));
      viewport?.removeComponentListener(listener!);
    }
  });
}