When I write long computation I break the line with \\ symbol like in this answer. However something has changed and now Math Processing Error pops out with such syntax. I see that between double dolar marks I can not write too many symbols.
Can you change it back, so that \\ will work again? And how should I write long computations now? By creating new double dolar marks?
EDIT I have just checked and it seems to be the problem with new Mozilla, cause everething looks fine in Chrome. However I still do not know how to fix it.