I think I have a good use case for this. Client want's to fetch youtube data by video id so their content managers don't have to add the same content twice. Data should not be editable to prevent Google duplicates. 

I added a timeout (500ms) before the form submit, because my form was submitted while the disabled-attributes were not fully removed.   $(document).on("click", ".cq-dialog-submit", function (e) { e.preventDefault(); const form = $(e.target).closest("form.cq-dialog"); cons...

Thanks for your great answer. I managed to fix the problem!Something else turned up now. When content editors copy a page and paste afterwards they can enter a new page name (url path). This field also needs the same validation. Do I have to repeat everything for a different category? Something like...

I'd like to only allow lowercase letters to this field. Is there a way add this or change the validation regular expression?The field has some validation, but I can't find where this is set. The field checks on spaces and wierd characters, but not uppercase letters. 

Is it possible to add some extra validation to the "Page name after move" field? I only want the user to be able to add lowercase Page names.