Ashley, something else to try...
Weird, I see it fail with both hitting Enter and clicking away, unless you click the other width or height box first.
If you type a number in Width, and hit enter (the fold up window closes immediately for me.) or you click away, (also closing the window,) it doesn't keep the number. If you click the Height first, (window doesn't close,) it will keep the number in the width.
Edit: If you Pin the window open, it works like you said Ashley.