Rating question display mode breaks css classes functionality

[SamMousa]

Are you requesting a feature, reporting a bug or asking a question?

Bug

What is the current behavior?

When setting displayMode to buttons the root css classes of a rating question are no longer applied.

What is the expected behavior?

It should just work.

How would you reproduce the current behavior (if this is a bug)?

See example below.

Provide the test code and the tested page URL (if applicable)

Tested page URL: https://codesandbox.io/p/sandbox/stoic-marco-wd7rwn

Specify your

• browser: Chrome
• browser version: latest
• surveyjs platform (angular or react or jquery or knockout or vue): knockout
• surveyjs version: latest

[SamMousa]

I've found through experimentation that in dropdown mode it applies the rootDropdown class. I feel that it should however also still apply the root class.

[SamMousa]

I'm not sure how the fix is supposed to work, but if I set something like this it doesn't work:

    survey.onUpdateQuestionCssClasses.add((sender, options) => {
            options.cssClasses.root += " test123";
    });

Checking the original demo which uses survey-core latest it still shows as broken.