Re: Emacs crashes when displaying the Euro character

[Richard Stallman]

With the X protocol, errors are reported asynchronously,
so an error caused by one X operation is detected by a later
operation.  The error has nothing to do with the X operation
in which it is detected.

If you can reproducibly cause an X protocol error,
try doing (x-synchronize t) and then make the failure happen.
That way the X error will be detected inside the primitive
that actually causes it, and you will get useful info from
the backtrace.