Activity chooser
From MoodleDocs
What is the Activity chooser?
A new feature in Moodle 2.3, the Activity chooser appears when the editing is turned on and the teacher clicks the link "Add an activity or resource" in the course section where they wish to add content:
The Activity chooser displays the available resource and activity options:
By clicking the radio button of an item, the teacher can read helpful information about that resource or activity and can then select it by clicking the "Add" button or double-clicking the radio button.
The Activity chooser may be turned on or off in Settings>Course administration.
If it is turned off, then the standard "Add an activity" and "Add a resource" drop down menus appear instead.