element中 popconfirm与tooltip一起使用

正常使用：

 <el-popconfirm title="确定删除吗？" >
            <el-button slot="reference" circle plain
                              size="mini"
                              type="danger"
                              icon="el-icon-delete"
                              @click="handleDelete(scope.row)"
                              v-hasPermi="['bus:box:remove']"></el-button>
          </el-popconfirm>

和tooltip一起使用，需要添加关键的reference：如下

<el-popconfirm confirmButtonText="确定" cancelButtonText="取消" icon="el-icon-info" iconColor="red" title="确定解绑车牌吗？">
            <template #reference>
              <div>
                <el-tooltip class="item" effect="dark" content="解绑车牌" placement="top-start" :enterable="false">
                  <el-button circle plain slot="reference"
                        v-if="scope.row.plateNum"
                        size="mini"
                        type="warning"
                        icon="el-icon-circle-close"
                        @click="handleUnboundPlateNum(scope.row)"
                        v-hasPermi="['bus:box:edit']"
                    />
                </el-tooltip>
              </div>
            </template>
          </el-popconfirm>