Yes, 2nd one existed (`disabled="disabled") for content-views. When we publish a content views containing same repo twice then UI won't allow us to add both published cv to composite-view and one of them will be disabled.

For e.g.
<input id="content_views_27" type="checkbox" value="1" tabindex="2" name="content_views[27]" data-view_id="27" disabled="disabled">