activeButtonsInReadOnly: ['source', 'preview'] is not working.

[patiencendiligence]

Hello, Somebody help me. plz.
(My jodit is the latest version. - free)

I want to the buttons such as 'source', 'preview' are working in readonly state.
So, I set like this my jodit editor config.

config: {
  readonly: true,
  activeButtonsInReadOnly: ['source', 'preview'],
  ...,
}

Then, The 'source' button works.
But.. The preview button looks like working - is active - . Actually, It is not working.
When I click the preview button, it is nothing happens. (not visible preview dialog..)

How can I make that preview button work in readonly state?
Thank you in advance.