Please be aware I am working with tutorial code here, so not everything is strictly correct, but it works. Most of the time.
I have a component class that is decorated as follows:
<button (click) = "onClickThere($event)">Click here!</button>
The selector "click-here" did not match any elements
This is only relevant to the element you instantiate with
If you bootstrap a component and it doesn't match a selector, Angular doesn't know where it should place it. Angular uses the selector to find the place where to insert the component into the DOM.
This also means you can currently bootstrap one component only once inside your page. There are plans to support overriding the selector when a component is passed to
bootstrap() but currently this isn't supported.
For components used inside
MyComponent this doesn't matter. You can have as many components as you want and only use what you need.