CSS Selectors Box Missing???

I have configured a WordPress website the same as I have with all other websites I have designed. I use the same theme and plugins as well. When I installed the Easy Google Fonts plugin, and go to “Settings -> Google Fonts” and click on “create a new font control”, it allows me to type a “Control Name”, but where it says:

Add CSS Selectors
Type each CSS selector that you would like this font control to manage in the box below. Use the tab key to separate each selector.

The box where I’d normally type the font control (i.e. .content), that box is missing. I cannot figure out how to fix or resolve this? I have opened numerous other instances of WordPress for other websites I administer, and it works fine.

I am hosting all these websites on the same server. I have uninstalled this plugin and re-installed it multiple times. I am at a loss as to why this is happening, and don’t know how t fix it.