bug#13484: 24.3.50; ESC <f10> is undefined

[Eli Zaretskii]

> Date: Fri, 18 Jan 2013 12:24:28 +0800
> From: Xue Fuqiao <xfq.free@gmail.com>
> 
> 
> The way to reproduce:
> emacs -Q
> ESC <f10>
> 
> Emacs says that it is undefined, but it should be defined:
> toggle-frame-maximized is an interactive compiled Lisp function in
> `frame.el'.
> It is bound to <M-f10>.

But Emacs doesn't think that ESC <f10> is <M-f10>:

  ESC <f10> (translated from <escape> <f10>) is undefined

Which AFAIU is the root cause of the problem, or maybe a feature.