msubsup-10

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

W3C sample	WIRIS
	$$p_x^3=\underset{\phantom{\text{l}}}{p_x^3}$$

<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
  <msubsup>
    <mi>p</mi>
    <mi>x</mi>
    <mn>3</mn>
  </msubsup>
  <mo>=</mo>
  <munder>
    <mrow>
      <msubsup>
        <mi>p</mi>
        <mi>x</mi>
        <mn>3</mn>
      </msubsup>
    </mrow>
    <mphantom>
      <mtext>l</mtext>
    </mphantom>
  </munder>
</math>

Author: George Chavchanidze, Opera Software ASA