bug#15273: 24.3.50; Combining character sequences are displayed weirdly

[Eli Zaretskii]

> Date: Thu, 5 Sep 2013 22:08:21 +0800
> From: Xue Fuqiao <xfq.free@gmail.com>
> 
>   emacs -Q
>   !                      ;; input an exclamation mark (#x21)
>   C-x 8 RET 2 0 E 4 RET  ;; COMBINING ENCLOSING UPWARD POINTING TRIANGLE
>   RET                    ;; Newline
>   C-x 8 2 6 A 0 RET      ;; WARNING SIGN
> 
> I tried many fonts, but all results look weird (the first line is
> incomplete and too large).

What font(s) were used to display this character?

If you go to the first line, which shows the character only partially,
and type C-a, does that fix the problem?

What about "M-x redraw-display RET"?

Finally, if you go to the first partially displayed character and type
"C-u C-x =", what does Emacs show?