bug Main page 'Sign In' and 'Join' menus become invisible when clicking outside the box

[moisevalentin]

The 'Sign In' and 'Join' panels become invisible when clicking outside of them, the functionality of the buttons remaining unchanged (See the attachments).
Please keep in mind that when the issue is occuring the user can not scroll or press any other button on the entire main page. Workaround: Refresh the page or estimate where the invisible buttons are located.