Comment 7 for bug 1654137

This is broken again as of revision 7398166ddf7c6dbbc9cae6ac69bb2feda14b40ac.

Bisection shows it was broken by commit df85a78bf83d85627de27f492e78e73bbbd3df4a,
"char: move mux to its own file". Somewhat confusingly, this commit predates the fix
(fb5e19d2e1472e96d72d5e4d89c20033f8ab345c), but it is part of a branch that was merged
after the fix, in merge commit 2d6752d38d8acda6aae674a72b72be05482a58eb. Apparently
this caused a reversion to an old version of the mux code that still has the bug.

Credit for discovering the regression goes to Paul Goyette.