Triple clicking in the text field of a onebox popup can return an "undefined" value

[alanorth]

Describe the bug
In DSpace 7.6, if you have an input field of type onebox that uses a controlled vocabulary, if you triple click in the input field, the modal is dismissed and an undefined value is filled. I have entities disabled and this seems to affect any input field using a onebox with a controlled vocabulary.

To Reproduce
Steps to reproduce the behavior:

1. Configure submission-forms.xml with an input field of type onebox that is using a controlled vocabulary. For example:

            <row>
                <field>
                    <dc-schema>dc</dc-schema>
                    <dc-element>subject</dc-element>
                    <dc-qualifier></dc-qualifier>
                    <repeatable>true</repeatable>
                    <label>Subject</label>
                    <vocabulary>srsc</vocabulary>
                    <input-type>onebox</input-type>
                    <required></required>
                </field>
            </row>

2. Click the text field to bring up the vocabulary select popup modal
3. Click three times in the text field (empty or not)
4. The dialog is dismissed and the value is set to "undefined"

The browser console shows an error TypeError: can't access property "isSelected"...

Video (webm/vp9):

submission.webm

Video (mp4):

submission.mp4

Expected behavior
Nothing should happen.