Annotations are model-wide objects but visibility of an annotation is view specific. Thus an annotation can be visible in the Structure view but invisible in an Annotation Group.
Visibility of an annotation can be toggled using its light bulb icon in the Browser or by choosing Annotations folder in the Structure Browser./ from the annotations node context menu. Visibility of all annotations can be toggled using the tree node light bulb icon next to the
See “Annotation Groups” for further discussion of visibility within annotation groups.