See bug 161045 comment 6.
Created attachment 287388 [details] WIP Patch
I have a patch almost ready doing this among other things that I'll upload at Bug 161669.
(In reply to comment #2) > I have a patch almost ready doing this among other things that I'll upload > at Bug 161669. Great. Would you mind integrating the trival change to MathMLMencloseElement.cpp into your work? Then I guess we can mark this one as a duplicate. Thanks.
Resolving per comment 2 *** This bug has been marked as a duplicate of bug 161669 ***