mspace-03

There should be no line break between 1 and 2

<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
  <mn>1</mn>
  <mspace linebreak="newline" width="thinmathspace"/>
  <mn>2</mn>
</math>

Author: George Chavchanidze, Opera Software ASA