OverlayPanel not working unless ShareModule is imported as well

[rekna1]

I'm submitting a ... (check one with "x")

[ x] bug report => Search github for a similar issue or PR before submitting
[ ] feature request => Please check if request is not on the roadmap already https://github.com/primefaces/primeng/wiki/Roadmap
[ ] support request => Please do not submit support request here, instead see http://forum.primefaces.org/viewforum.php?f=35

Plunkr Case (Bug Reports)
In my case p-overlayPanel is not working (shows empty content) unless I also import ShareModule from primeng/api , which is not mentioned in the documentation...

import { SharedModule } from "primeng/api";

@NgModule({
  imports: [
    ...
    SharedModule,
    OverlayPanelModule,
    ....
  ],