Backbone model for the CKEditor toolbar configuration state.
The textarea that contains the serialized representation of the active CKEditor configuration.
The CKEditor configuration that is being manipulated through the UI.
A hash that maps buttons to features.
A hash, keyed by a feature name, that details CKEditor plugin features.
Whether the button group names are currently visible.
The configuration for the hidden CKEditor instance that is used to build the features metadata.
Tracks whether the active toolbar DOM structure has been changed. When true, activeEditorConfig needs to be updated, and when that is updated, $textarea will also be updated.