I sometimes find that when I am saving files off the web in Firefox, I have to go through multiple levels of folder creation. I click the “create new directory” button, type a name, hit return. Repeat.
I just learned (after my determination that it would be a very handy thing) that you can simply enter a directory hierarchy (e.g. images/wallpapers/hairless_cats/1024x768/) and firefox will create all of the parent directories and leave you in the deepest directory (“1024x768”). What a useful feature!
That’s good design. I do what intuitively seems right and I find exactly the feature I am looking for.