In Wicket 6.10.0 (per https://issues.apache.org/jira/browse/WICKET-5289), sets the HTML5 "required" attribute. This causes HTML5 browsers such as Chrome to display a client-side pop-up.
When the OK button is clicked, the Wicket viewer always displays the veil (see jquery.isis.viewer.wicket.js), and relies upon a page refresh to clear the veil.
However, because the page is never submitted, the veil does not disappear. The only workaround is to resubmit the page, thus losing any text that might have been entered.
In Wicket 6.11.0, a new HTML5Attributes feature (
WICKET-5331) makes this behaviour pluggable.
This ticket was previously to disable the setRequired flag for Wicket 6.10.0.
With the advent of Wicket 6.11.0, it is instead to upgrade to Wicket 6.11.0 and to use this new feature.