code: function handleDocumentOpen(commandData) {
          var result = new $.Deferred();
          handleFileOpen(commandData)
              .done(function (file) {
                  // if we succeeded with an open file
                  //  then we need to resolve that to a document.
                  //  getOpenDocumentForPath will return null if there isn't a
                  //  supporting document for that file (e.g. an image)
                  var doc = DocumentManager.getOpenDocumentForPath(file.fullPath);
                  result.resolve(doc);
              })
              .fail(function (err) {
                  result.reject(err);
              });
  
          return result.promise();
  
      }
docs: Opens the given file, makes it the current file, does NOT add it to the workingset
  @param {FileCommandData} commandData
  fullPath: File to open;
  silent: optional flag to suppress error messages;
  paneId: optional PaneId (defaults to active pane)
  @return {$.Promise} a jQuery promise that will be resolved with @type {Document}