When creating a component, it is automatically added to app.module.ts. When/If you delete the component (right-click folder and delete) you are prompted about the deletion. After confirming the deletion, the component is still listed in the app.module.ts. It is not a big deal, but would be nice if it was both removed there as well.
Our component creation support is based on angular-cli. Removal/deletion is not yet supported by angular-cli and it is unlikely that they will provide support for it in the near future. At this stage, I am afraid we cannot provide custom support for removal from our side.
Sorry about it. Please let us know if you see any other issues.