"Add Existing Lesson" popup doesn't close after selecting a lesson

[brianhogg]

Reproduction Steps

1. In the course builder click Add Existing Lesson
2. Choose a lesson

Expected Behavior

Lesson shows and Add Existing Lesson popup closes

Actual Behavior

The "Add Existing Lesson" popup remains open.

[brianhogg]

Needed to physically remove the elements, seems like something internal to webui-popover.