Heh, That's because u is hard-coded to close the 2d window.
2d windows don't use the bind system, unfortunately.
I will fix the Player Score list window and any others on a case-by-case basis.
Thanks for the bug report.

I have bound the key for "show players score" to something other than the default "u", but now when I open it (with my new key, "x") it won't close with "x", only with "esc". This is strange since when it was/is bound to "u", the button opens and closes the screen while having it bound to "x" only allows me to open the screen and not close it.

Steps to reproduce:
1. Bind "show players scores" to x.
2. Press "x".
3. Press "x" again.

Expected results:
scores screen opens on step 2 and closes on step 3.

Actual results:
scores open on step 2 and stays open on step 3.

Type a "/bind u" to see if there is anything else binded to u

Nope.. nothing. u and x are bound to the same thing, however, u can close the window and x can't.