Angular ng材质树在角度应用中显示错误

我试图在角度应用中集成ng材质treetable。 但它显示出的错误是

core.js:15723 ERROR Error: Uncaught (in promise): Error: BrowserModule has already been loaded. If you need access to common directives such as NgIf and NgFor from a lazy loaded module, import CommonModule instead.

但我只在app.modules.ts中添加了

BrowserModule、BrowserAnimationsModule

在搜索引擎中搜索得到一些想法后，下面的链接也出现了不一样的错误

Package.json供参考

"devDependencies": {
        "@angular-devkit/build-angular": "^0.13.5",
        "@angular/cli": "^7.2.2",
        "@angular/compiler-cli": "^7.0.0",
        "@angular/language-service": "^7.0.0",
        "@ckeditor/ckeditor5-angular": "^1.0.0",
        "@ckeditor/ckeditor5-build-classic": "^11.1.1",
        "@types/c3": "^0.6.0",
        "@types/chartist": "^0.9.37",
        "@types/datatables.net": "^1.10.10",
        "@types/jasmine": "~2.8.6",
        "@types/jasminewd2": "~2.0.3",
        "@types/jquery": "^3.3.6",
        "@types/node": "^8.10.43",
        "codelyzer": "~4.2.1",
        "jasmine-core": "~2.99.1",
        "jasmine-spec-reporter": "~4.2.1",
        "karma": "~1.7.1",
        "karma-chrome-launcher": "~2.2.0",
        "karma-coverage-istanbul-reporter": "~1.4.2",
        "karma-jasmine": "~1.1.1",
        "karma-jasmine-html-reporter": "^0.2.2",
        "protractor": "^5.4.0",
        "ts-node": "~7.0.0",
        "typescript": "~3.1.1"
    }
}

---

提前感谢。

开发人员正在将BrowserModule导入他的软件包中。角度应用程序只能包含一个导入（）。如果您查看他的回购协议，开发人员已经收到通知：

感谢您宝贵的回答。所以你能给我推荐一个角度树表的例子吗。