Before this commit the button custom color colorpickers were not updated when a color was selected - but this was alright because the colorpickers did not remain opened. After this commit the button custom color colorpickers are updated whenever a color is picked, which is necessary during gradient edition. task-2599771 X-original-commit: f40c980d7ff68f27b389a93cd2b8f60cbff5baa6 Part-of: odoo/odoo#76608