When items are added/removed from a tableview's item list, editing is cancelled. This results in odd behavior when using a combo box. The combo box opens up but when the update to the item list occurs, the combo box bugs out leaving an un-editable drop down (see test case): -

import javafx.application.Application;
import javafx.application.Platform;
import javafx.collections.FXCollections;
import javafx.scene.control.ComboBox;
import javafx.scene.control.ContentDisplay;
import javafx.scene.control.TableCell;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableView;
import javafx.scene.control.cell.PropertyValueFactory;
import javafx.stage.Stage;

class EditableComboBoxCell extends TableCell<String, String>
{

  private ComboBox<Object> comboBox;

  @Override
  public void startEdit()
  {
    super.startEdit();
    comboBox = new ComboBox<>();
    setContentDisplay(ContentDisplay.GRAPHIC_ONLY);
    setGraphic(comboBox);
  }

  @Override
  public void cancelEdit()
  {
    super.cancelEdit();
    comboBox = null;
    setContentDisplay(ContentDisplay.TEXT_ONLY);
    setText(getItem());
  }

  @Override
  public void updateItem(final String item, final boolean empty)
  {
    super.updateItem(item, empty);
    if (empty)
    {
      setText(null);
      setGraphic(null);
    }
    else
    {
      if (isEditing())
      {
        setContentDisplay(ContentDisplay.GRAPHIC_ONLY);
        setGraphic(comboBox);
      }
      else
      {
        setContentDisplay(ContentDisplay.TEXT_ONLY);
        setText(getItem());
      }
    }
  }
}

public class Foo extends Application implements Runnable
{

  @Override
  public void start(final Stage stage)
  {
    final TableView table = new TableView();
    final TableColumn column = new TableColumn();
    table.setEditable(true);
    column.setEditable(true);

    table.setItems(FXCollections.observableArrayList());

    column.setCellFactory(cell -> new EditableComboBoxCell());
    column.setCellValueFactory(param -> new SimpleStringProperty("foo"));

    table.getColumns().add(column);

    // Simple thread loop to demonstrate adding items

    new Thread(() ->
    {
        try
        {
            while (true)
            {
                Thread.sleep(5000);
                Platform.runLater(() -> table.getItems().add("foo"));
            }

        } catch (InterruptedException e)
        {
        }
    }).start();

    Scene scene = new Scene(new StackPane(table));

    stage.setScene(scene);

    stage.show();

  }

  @Override
  public void run()
  {
    launch();
  }
}

A suggestion on stackoverflow as a more sophisticated fix is attached below: -

"if the content change removes the item that is being edited, cancel edit, otherwise make sure the correct cell is now in editing state"

See the following post on stackoverflow: -

http://stackoverflow.com/questions/30073165/javafx-controls-inside-tableview-behaving-strangely

Classifying this as major as in a fast updating table view, an editable combo box table cell is unusable as the pop out box where you select an item just closes upon update. I noticed in versions prior to 8u60 (early access), the combo box would jump around on the tableview.