When there are two alternative regex patterns, allowed attribute values are displayed incorrectly in HTML attributes table

Given my example RNG, there is a conversion issue where attributes table only displays one of two alternative patterns. However, the SVG diagram correctly shows both patterns (although it displays both with the label "token", so while correct, that's not too helpful either in the end).

  <define name="pattern1">
    <data type="token">
      <param name="pattern">A_PATTERN</param>
    </data>
  </define>
  <define name="pattern2">
    <data type="token">
      <param name="pattern">ANOTHER_PATTERN</param>
    </data>
  </define>

[....]


  <define name="ds.myelement">
    <element name="myelement">
      <attribute name="myattribute">
        <choice>
          <ref name="pattern2"/>
          <ref name="pattern1"/>
        </choice>
      </attribute>
      <empty/>
    </element>
  </define>

The attribute table for myelement's myattribute then claims that only pattern2 (the one mentioned first within <choice/>) is present:

Data type	token
Parameters	ANOTHER_PATTERN