DetailHandler refresh bug

[sarahfuchs]

Bug:
Grid with detail handler: setItems and set another list of partly the same items scrambles the displayed details. Somtimes the UI looks broken, sometimes the contents of the details is faulty.

• Vaadin Framework version: 8.12.3
• Browser version: Chrome 88.0.4324.190
• Web container name and version: Tomcat, v9.0
• Description of the bug: Displays faulty details
• Expected behavior: Display correct details. In the example, the row contains a collection of strings and the diplayed value is a space seperated list. The details are the same entries, but listed in a vertical layout.
• Actual behavior: After resetting the items with a sub set of previous items, the displayed details do no longer fit to the row.

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Minimal reproducible example

private VerticalLayout createExamplleLayout() {
Collection firstCollection = Arrays.asList("Hello", ",", "world!");
Collection secondCollection = Arrays.asList("My", "name", "is", "Sarah");
Collection thirdCollection = Arrays.asList("red", "blue");
Collection fourthCollection = Arrays.asList("spring", "summer", "automn", "winter");

VerticalLayout mainLayout = new VerticalLayout();
Grid<Collection<String>> grid = new Grid();
grid.setDetailsGenerator(collection -> {
  VerticalLayout detailLayout = new VerticalLayout();
  collection.forEach(item -> detailLayout.addComponent(new Label(item)));
  return detailLayout;
});
ValueProvider<Collection<String>, String> valueProvider = collection -> String.join(" ", collection);
grid.addColumn(valueProvider);

List<Collection<String>> itemsInitial = Arrays.asList(firstCollection, secondCollection, thirdCollection, fourthCollection);
grid.setItems(itemsInitial);
for (Collection<String> tmp : itemsInitial) {
  grid.setDetailsVisible(tmp, true);
}
mainLayout.addComponent(grid);

Button clickButton = new Button("click", event -> {
  List<Collection<String>> itemsOverwrite = Arrays.asList(secondCollection, fourthCollection);
  grid.setItems(itemsOverwrite);
  for (Collection<String> tmp : itemsOverwrite) {
    grid.setDetailsVisible(tmp, true);
  }
});
mainLayout.addComponent(clickButton);

return mainLayout;

}

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