sclass JContentAndControls is Swingable, Updateable {
  settable IF0/*<JComponent or Swingable>*/ makeContent;
  SingleComponentPanel scpContent = singleComponentPanel();
  ReliableSingleThread rstReloadContent = rst(l0 reloadImpl);
  settable JButton btnReload;
  gettable DynamicHStack controls = dynamicHStack();
  gettable JPanel rightCornerControls = jline();
  SingleComponentPanel scpControls = singleComponentPanel(jfullcenter(controls));
  
  settable bool loadingScreenWhenReloading;
  settable bool showControls = true;
  settable bool showReloadButton = true;
  
  public void reload aka update() { rstReloadContent.trigger(); }
  
  cachedVisualize {
    onComponentShown(scpContent, -> { if (scpContent.isEmpty()) reload(); });
    
    if (!showControls) ret scpContent;
    
    if (showReloadButton) {
      btnReload = jReloadButton(l0 reload);
      add(rightCornerControls, btnReload);
    }
    
    ret northAndCenter(withMargin(
      centerAndEastWithMargin(scpControls, rightCornerControls)), scpContent);
  }
  
  swappable JComponent makeLoadingScreen() {
    ret jCenteredLabel("Loading...");
  }
    
  void reloadImpl {
    temp tempDisableButton(btnReload);
    
    if (loadingScreenWhenReloading() || !scpContent.hasComponent())
      scpContent.set(makeLoadingScreen());
      
    try {
      scpContent.set(wrap(makeContent?!));
    } catch print e {
      scpContent.set(jErrorView(e));
    }
  }
  
  selfType addControl(S label, JComponent etc control) {
    ret addControl(withLabel(label, control));
  }
  
  selfType addControl(JComponent etc control) {
    controls.addComponent(control);
    this;
  }
  
  selfType content(IF0 makeContent) {
    ret makeContent(makeContent);
  }
  
  selfType addControlLine(JComponent newControls) {
    scpControls.set(centerAndSouthWithMargin(scpControls!, newControls);
    this;
  }
}

Began life as a copy of #1036191