Unchecking "Display Site Title and Tagline" makes the whole Header disappear

[prtksxna]

Open Customizer -> Site Identity -> Uncheck Display Site Title and Tagline, and the entire header disappears.

This is happening because when display_header_text is false the whole .header is put out of view, instead of just .header__title and .header__description. This is easily fixed by targeting the correct classes in inc/custom-header.php and in js/customizer.js.

The problem is that WordPress hides and removes the header_textcolor customizer setting when display_header_text is set to false. This means that the menu, or any other content that could have used that color no longer has access to it. So, essentially, to solve for this we'll need to add another customizer setting, something like header_textcolor_secondary.

[prtksxna]

A quick hack to just remove the title and tagline on the homepage would be to add the following Additional CSS in the customizer:

.header__title,
.header__description {
    display: none;
}

[prtksxna]

See also https://core.trac.wordpress.org/ticket/44968