On page load document disappears until i press CTRL+Z and then everything works as expected

[virtuman]

almost every time when i load a page the contents of the CM area disappears, but after i press CTRL+Z everything re-appears and works as expected.
any idea what i'm doing wrong here?

thank you.

window.Debugger = (function() {

  return {
    init: function() {
      //init resizer
      $(".debug-panel:not(:first)").splitter().data('splitter')
      .trigger('init')
      .on('resize-start', function() {
        $('#left-area .overlay').show();
      })
      .on('resize-end', function() {
        $('#left-area .overlay').hide();
      });

      //codemirror
      CodeMirror.keyMap.basic.Tab = 'indentMore';
      this.init_python_editor($("#python-editor"));
      ...
    },

    not_saved: false,
    init_python_editor: function($el) {
      var _this = this;
      var cm = this.python_editor = CodeMirror($el[0], {
        value: script_content,
        mode: "python",
        indentUnit: 4,
        lineWrapping: true,
        styleActiveLine: true,
        lineNumbers: true,
        autofocus: true
      });

      var s = new BCSocket("http://" + location.hostname + ":7007/channel", {origin: "http://" + location.hostname + ":7007/channel",
            crossdomainXhr: true,
            reconnect: true
      });
//
    var sjs = new window.sharejs.Connection(s);
    var doc = sjs.get('users', project_name);

      doc.subscribe();

      doc.whenReady(function () {
        if (!doc.type) doc.create('text');
        if (doc.type && doc.type.name === 'text') {
            doc.attachCodeMirror(cm);
        }
      });

.....