I am sure I didn't modify anything except updated nuget package to 18.2.0.54. I compacted the project and send you back, you can check for it. And I'm sure the console error comes because I repeated the experiment more times than necessary. But I still noticed something:
1. the odds for the error to appear indeed lower than before your fix.
2. the console error content focuses on "cannot read property 'xxx' of null", and xxx could be style or closest. (I attached a clear to read screenshot for your information.)
3. If the solution is cleared and rebuilt, the odds get higher (maybe the bug is hidden due to something been cached?)
This is what I do to reproduce the error:
1. clear the solution and press F5 to rebuild and run it.
2. while the new browser windows opens, press F12 to open the developer tools.
3. wait for the first page to be loaded (the Grid).
4. start clicking different labels from the menu randomly.
5. and the error appears.
I have recorded my steps into a video to show you. What worth mention is that my developing machine is not so powerful, so the loading speed is relatively low. I suspect maybe it's a factor to cause the error because I could reach some (imaginary) "loading gap" more easily than you guys. That is, maybe the loading and switching performance of yours is too good to catch the moment (just guess).
Here is my environment:
Windows 7 Service Pack 1 x64 professional
Visual Studio 2019 preview 16.6.0 Preview 2.1
dotnet core sdk v 3.1.300
Google Chrome 83.0.4103.7 stable
Attachment:
ConsoleErrorSteps_86fd0e4f.rar