In the Family Editor, click Create tab
Family Editor panel
Shape Status.
The Shape Status tool supplies two means of validating a rebar shape. First, it indicates whether the current state of the shape is a valid rebar shape. If the control is disabled, the shape is valid and you can load it into projects. If the Shape Status control is active, something is wrong with the current shape. See Warnings for Selected Elements.
Second, when active (indicating an error), click it to launch an error dialog. This dialog is similar to the Review Warnings command, displaying all current errors within the shape.