A page might have hidden widgets on it. You can set the page to display these widgets and also convert hidden widgets so that they are always visible.
An option on the page menu determines whether the page displays only the visible widgets or it displays all widgets, including the hidden widgets. If the page is displaying all widgets, you can distinguish the hidden widgets from the visible widgets by looking at their frames. A visible widget has a solid frame while a hidden widget has a dashed frame. In the following screen capture, the widget on the left is a visible widget while the widget on the right is a hidden widget.
To reveal hidden widgets: