Function userCanSelect

static/editor.md/editormd.js:4462–4464

(obj)

            });

            var userCanSelect = function (obj) {
                obj.removeClass(classPrefix + "user-unselect").off("selectstart");
            };

            var userUnselect = function (obj) {
                obj.addClass(classPrefix + "user-unselect").on("selectstart", function(event) { // selectstart for IE