msub-12

Formatting of right hand side of equation should be identical to formatting of left hand side

W3C sample	WIRIS
	$$P_0=\underset{\phantom{x}}{\overset{\phantom{x}}{P_0}}$$

<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
  <msub>
    <mi>P</mi>
    <mn>0</mn>
  </msub>
  <mo>=</mo>
  <munderover>
    <mrow>
      <msub>
        <mi>P</mi>
        <mn>0</mn>
      </msub>
    </mrow>
    <mphantom>
      <mi>x</mi>
    </mphantom>
    <mphantom>
      <mi>x</mi>
    </mphantom>
  </munderover>
</math>

Author: George Chavchanidze, Opera Software ASA