code: function _calcScaling() {
          var $sb = _getScrollbar(editor);
  
          trackHt = $sb[0].offsetHeight;
  
          if (trackHt > 0) {
              trackOffset = getScrollbarTrackOffset();
              trackHt -= trackOffset * 2;
          } else {
              // No scrollbar: use the height of the entire code content
              var codeContainer = $(editor.getRootElement()).find("> .CodeMirror-scroll > .CodeMirror-sizer > div > .CodeMirror-lines > div")[0];
              trackHt = codeContainer.offsetHeight;
              trackOffset = codeContainer.offsetTop;
          }
      }
docs: Measure scrollbar track