Adding Scrollable overlays breaks canOutsideClickClose with hasBackdrop false

[ghost]

Bug report

• Package version(s): Chrome
• Browser and OS versions: OSX

Steps to reproduce

Code from the github overlay docs:

<Overlay className="pt-overlay-scroll-container" isOpen={this.state.isOpen}  hasBackdrop={false} onClose={this.handleClose}>
...
</Overlay
..... 
handleClose = () => this.setState({ isOpen: false });

Actual behavior

• canOutsideClickClose no longer closes the overlay.

Expected behavior

• canOutsideClickClose closing the overlay.

Workaround

Use backdropClassName to set background:transparent.

Thank you :)