Specifically, you’re unable to select the textbox that says “color” and type a new term, and clicking the tabs (tutorials, videos, recipes, API documentation) doesn’t work.
This doesn’t seem to be a 100% reproducible thing, because at some points I have been able to successfully use a lot of the textboxes once or even several times.
When it’s broken, using Inspect Element will select the div housing the input field, not the input field itself. Unsure if that has anything to do with it. I haven’t had a chance to inspect a page where the issue is not present, but I’m still looking.