Outputs the settings form for the Calendar widget.

Handles updating settings for the current Calendar widget instance.

Outputs the content for the current Calendar widget instance.

Core class used to implement a Categories widget.

Sets up a new Categories widget instance.

Outputs the settings form for the Categories widget.

Handles updating settings for the current Categories widget instance.

Outputs the content for the current Categories widget instance.

Singleton that registers and instantiates WP_Widget classes.

Serves as a utility method for adding widgets to the registered widgets global.