The Unhide command enables you to restore the visibility of a grayed out item icon in the Annotation Tree Panel and to unhide the corresponding annotation or all the annotations belonging to the corresponding category, if the selected item icon is a category node (see Hide).
To start the command, right-click on the grayed out item icon of an annotation or category and select Unhide in the context menu.
Please also note that double-clicking on the corresponding tree item icon will toggle visibility of an annotation (exactly as right-clicking and selecting Hide in the context menu). If you double-click on the icon of a category or the main node then the visibility of all of its children will be modified to match the presently toggled visibility mode of the clicked item.