Ver. Joomla 4.0 Alpha 12

Steps to reproduce the issue

Using the example at the bottom of this page: https://docs.joomla.org/List_form_field_type

<field
    name="fielda"
    type="list"
    label="FIELDA_LABEL"
    description="FIELDA_DESC"
    >
    <option value="editor">TYPE_EDITOR</option>
    <option value="text">TYPE_TEXT</option>
    <option value="textarea">TYPE_TEXTAREA</option>
</field>

<field
    name="fieldb"
    type="list"
    label="FIELDB_LABEL"
    description="FIELDB_DESC"
    >
    <option value="0">JNO</option>
    <option value="1">Option 1</option>
    <option
        showon="fielda:text,textarea"
        value="2">Option 2</option>
    <option
        showon="fielda:text"
        value="3">Option 3</option>
</field>

Expected result

Expected result is as described on the page:

• "Option 3" of fieldb is only displayed if option "TYPE_TEXT" is selected in fielda.

• "Option 2" of fieldb is only displayed if option "TYPE_TEXT" OR "TYPE_TEXTAREA" is selected in fielda.

• "Option 1" and "JNO" of fieldb is always displayed.

Actual result

All options of fieldb are displayed no matter what.

Additional comments

Workaround is to add showon for fieldb itself: <field name="fieldb" showon="fielda:editor,text,textarea" [...]. The showon attribute on fieldb's options will then work as expected.