[OJS] Problem with HTML Article Galley

Several days ago I saw this topic here, but no way to find it now. If I enable html Article Galley plugin, html galleys are displayed in very small window within the page.

Looks something is wrong with iframe - looks like fullscreen does not work.

Thanks for help

Only one idea - cannot be problem in this?

This attribute can be set to true if the frame is allowed to be placed into full screen mode by calling its Element.requestFullscreen() method. If this isn’t set, the element can’t be placed into full screen mode.