Program: 62387
Project: 62387
Buggy source:
public void addTab(Path path){
  ObservableList<String> recentFiles=controller.getRecentFiles();
  if (Files.notExists(path)) {
    recentFiles.remove(path.toString());
    return;
  }
  ObservableList<Tab> tabs=controller.getTabPane().getTabs();
  for (  Tab tab : tabs) {
    MyTab myTab=(MyTab)tab;
    Path currentPath=myTab.getPath();
    if (Objects.nonNull(currentPath))     if (currentPath.equals(path)) {
      myTab.select();
      return;
    }
  }
  AnchorPane anchorPane=new AnchorPane();
  WebView webView=webviewService.createWebView();
  WebEngine webEngine=webView.getEngine();
  MyTab tab=createTab();
  tab.setWebView(webView);
  webEngine.setConfirmHandler(param -> {
    if ("String_Node_Str".equals(param)) {
      JSObject window=(JSObject)webEngine.executeScript("String_Node_Str");
      window.setMember("String_Node_Str",controller);
      window.call("String_Node_Str",new Object[]{});
      Map<String,String> shortCuts=controller.getShortCuts();
      Set<String> keySet=shortCuts.keySet();
      for (      String key : keySet) {
        window.call("String_Node_Str",new Object[]{key,shortCuts.get(key)});
      }
      if (Objects.isNull(path))       return true;
      threadService.runTaskLater(() -> {
        String content=IOHelper.readFile(path);
        threadService.runActionLater(() -> {
          tab.setTabText(path.getFileName().toString());
          window.call("String_Node_Str",new Object[]{content});
          window.call("String_Node_Str");
          TabPane tabPane=controller.getTabPane();
          tabPane.getTabs().add(tab);
          tab.select();
        }
);
      }
);
    }
    return false;
  }
);
  Node editorVBox=editorService.createEditorVBox(webView,tab);
  controller.fitToParent(editorVBox);
  anchorPane.getChildren().add(editorVBox);
  tab.setContent(anchorPane);
  tab.setPath(path);
  Tooltip tip=new Tooltip(path.toString());
  Tooltip.install(tab.getGraphic(),tip);
  recentFiles.remove(path.toString());
  recentFiles.add(0,path.toString());
  webView.requestFocus();
}

Fixed version (ground truth):
public void addTab(Path path){
  ObservableList<String> recentFiles=controller.getRecentFiles();
  if (Files.notExists(path)) {
    recentFiles.remove(path.toString());
    return;
  }
  ObservableList<Tab> tabs=controller.getTabPane().getTabs();
  for (  Tab tab : tabs) {
    MyTab myTab=(MyTab)tab;
    Path currentPath=myTab.getPath();
    if (Objects.nonNull(currentPath))     if (currentPath.equals(path)) {
      myTab.select();
      return;
    }
  }
  AnchorPane anchorPane=new AnchorPane();
  WebView webView=webviewService.createWebView();
  WebEngine webEngine=webView.getEngine();
  MyTab tab=createTab();
  tab.setWebView(webView);
  tab.setTabText(path.getFileName().toString());
  webEngine.setConfirmHandler(param -> {
    if ("String_Node_Str".equals(param)) {
      JSObject window=(JSObject)webEngine.executeScript("String_Node_Str");
      window.setMember("String_Node_Str",controller);
      window.call("String_Node_Str",new Object[]{});
      Map<String,String> shortCuts=controller.getShortCuts();
      Set<String> keySet=shortCuts.keySet();
      for (      String key : keySet) {
        window.call("String_Node_Str",new Object[]{key,shortCuts.get(key)});
      }
      if (Objects.isNull(path))       return true;
      threadService.runTaskLater(() -> {
        String content=IOHelper.readFile(path);
        threadService.runActionLater(() -> {
          window.call("String_Node_Str",new Object[]{content});
          window.call("String_Node_Str");
        }
);
      }
);
    }
    return false;
  }
);
  threadService.runActionLater(() -> {
    TabPane tabPane=controller.getTabPane();
    tabPane.getTabs().add(tab);
    tab.select();
  }
);
  Node editorVBox=editorService.createEditorVBox(webView,tab);
  controller.fitToParent(editorVBox);
  anchorPane.getChildren().add(editorVBox);
  tab.setContent(anchorPane);
  tab.setPath(path);
  Tooltip tip=new Tooltip(path.toString());
  Tooltip.install(tab.getGraphic(),tip);
  recentFiles.remove(path.toString());
  recentFiles.add(0,path.toString());
  webView.requestFocus();
}