_onFabricMouseDown(fEvent) {
    const obj = fEvent.target;

    if (obj && !obj.isType('text')) {
      return;
    }

    if (this.isPrevEditing) {
      this.isPrevEditing = false;

      return;
    }

    this._fireAddText(fEvent);
  }
Fabric 'mousedown' event handler
@param {fabric.Event} fEvent - Current mousedown event on selected object
@private