Forum Discussion
Modal dialog does not work in SPFx web part
If you have Chrome,can you run chrome using disablewebsecurity which will disable the CORS issues for time being to verify that your content has been working properly or not in a Dialog
So you code is failing because of CORS issue,not because of the react component not getting rendered.
Teaching bubble is more of a tooltip kind of thing to display.Here is the link.
https://developer.microsoft.com/en-us/fabric#/controls/web/teachingbubble
O365Developer I am actually using the new edge to test my development.
once developed, my users will need to run with disabled web security. 
I want you to run with disablewebsecurity in Chrome to make sure that your code is working fine without any issues.
Disabling CORS in IE not possible ,or may be possible with newer version of Edge.
https://superuser.com/questions/1020612/can-the-same-origin-request-policy-be-disabled-in-microsoft-edge
If the code is running fine, and in order to handle the CORS issue,we can use some proxies like heroku or you can develop your own custom proxy,however that needs to be hosted on some server.