Since the latest OWL refactoring, "button" DOM element in tree views cannot be defined without an associated action (it will crash on click). In the survey module, we use a "fake" button to mark a question as conditional (based on the answer of another question). The button functions as a simple icon and has no attached action. To fix the issue, we now mark the button as "disabled" so the click action will not trigger anything. Task-2618108 closes odoo/odoo#75158 Related: odoo/enterprise#20049 Signed-off-by: Thibault Delavallee (tde) <tde@openerp.com>