Dropdowns do not work in fullscreen mode

Hi,

If I try editing in Fullscreen mode, all the dropdowns stop working. I have tried editing in different browsers, different themes, default themes, and different servers as well. All sites with 4.8.1 fail show dropdown options from menus and from buttons as well such as font size, font, formatting and formats. I tried editing in older version 4.6.6 of WordPress which shows dropdown without any issue, hope this has been reported already and gets fixed soon. Any quick solution to it?

Thanks.