Select the object or connection whose attribute you want to delete. If you want to delete model attributes, you must ensure that no object or connection is selected so that the model attributes will be displayed on the Attributes tab of the Properties bar.
Click Properties. The Properties bar opens.
Click the Attributes tab if it is not activated yet.
Behind the attribute you want to delete, click More.
Click Delete attribute.
The value of the attribute will be deleted. You cannot change or delete attribute values of attributes that the system defines. These are placed in gray cells, for example, Last change.