code: function _makeFirstPaneResizable() {
          var firstPane = _panes[FIRST_PANE];
          Resizer.makeResizable(firstPane.$el,
                                _orientation === HORIZONTAL ? Resizer.DIRECTION_VERTICAL : Resizer.DIRECTION_HORIZONTAL,
                                _orientation === HORIZONTAL ? Resizer.POSITION_BOTTOM : Resizer.POSITION_RIGHT,
                                MIN_PANE_SIZE, false, false, false, true, true);
  
          firstPane.$el.on("panelResizeUpdate", function () {
              _updateLayout();
          });
      }
docs: Makes the first pane resizable
  @private