code: function (context) {
                  var oElement;
                  var oFocusControl;
                  var that = context;
                  var defaultFocusableElements = [that._mParameters.firstFocusable, that._mParameters.lastFocusable];
                  // jQuery custom selectors ":sapTabbable"
                  var aTabbables = jQuery(":sapTabbable", that.$()).get();
  
                  // search the first tabbable element
                  for (var i = 0; i < aTabbables.length; i++) {
                      if (defaultFocusableElements.indexOf(aTabbables[i].id) === -1) {
                          oElement = aTabbables[i];
                          break;
                      }
                  }
  
                  // If a tabbable element is part of a control, focus the control instead
                  // jQuery Plugin "control"
                  oFocusControl = jQuery(oElement).control();
                  if (oFocusControl[0]) {
                      var oFocusDomRef = oFocusControl[0].getFocusDomRef();
                      oElement = oFocusDomRef || oElement;
                  } else {
                      // if there is no tabbable element in the content use the first fake
                      // element to set the focus to the toolpopup
                      oElement = defaultFocusableElements[0] ? window.document.getElementById(defaultFocusableElements[0]) : null;
                  }
  
                  // oElement might not be available if this function is called during destroy
                  if (oElement) {
                      if (oElement) {
                          oElement.focus();
                      }
                      that._sInitialFocusId = oElement.id;
                  }
              }
docs: Determines the new element which will gain the focus.
  
  @param {sap.ui.ux3.ToolPopup} context to get/set instance values
  @private