1872643 - width of empty <mo>

Status: UNCONFIRMED

(Core :: MathML, defect)

Description

[15063662]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:121.0) Gecko/20100101 Firefox/121.0

Steps to reproduce:

<math>
  <mrow>
    <mi>a</mi>
    <mo lspace="1em" rspace="1em"></mo>
    <mi>b</mi>
  </mrow>
</math>

Actual results:

<mo lspace="1em" rspace="1em"></mo> has zero width in Firefox

Expected results:

<mo lspace="1em" rspace="1em"></mo> should have width 2em (as in Chrome)

Comment 1

[Frédéric Wang (:fredw)]

If I add a style="background: red" to the <mo> or use the inspector, I still see empty size for Chrome.

lspace/rspace are instead used during the layout of the mrow:

https://w3c.github.io/mathml-core/#layout-of-mrow

which Firefox probably does not follow.