in public/src/js/models/common-handlers.js [60:73]
$(el).keydown(function(e) {
var keyCode = e.keyCode || e.which,
formField,
formFields,
nextIndex;
if (keyCode === 9) {
e.preventDefault();
formField = bindingContext.$rawData;
formFields = _.filter(article.editors(), ed => ed.type === 'text' && ed.displayEditor());
nextIndex = mod(formFields.indexOf(formField) + (e.shiftKey ? -1 : 1), formFields.length);
mediator.emit('ui:open', formFields[nextIndex].meta, article, article.front);
}
});