It’s definitely not a jump menu. I searched for this and what I found did not match what I was looking for. Maybe the way I described it was confusing.
There are no arrows or anything like that. A line of text is in a box and it is clickable, clicking the box reveals more text to appear below this text (as expanding the category to revel further details) All within the main text area of the website.
I can’t really describe what I’m looking for but I can’t find the examples that I had seen before. It’s something that you will come across on some websites but now that I’m looking for it I can’t find any examples. I’ll have to wait until I come across this and then post an example.