Controls placed on top of QLPreviewView are not hittable.

I experience strange QLPreviewView behavior starting from macOS High Sierra 10.13, where controls placed on top of it are not hittable at all.

Steps to reproduce:

1. Create a simple container NSView
2. Add QLPreviewView to the container
3. Add NSButton to the container and place it over QLPreviewView

I've created the video which is more descriptive:

https://www.dropbox.com/s/e5fpvce9zswm4lc/qlpreview.mov?dl=0

And the demo application project:

https://www.dropbox.com/s/yl8y664mwarsbjv/ExampleAppSources.zip?dl=0

And I've also placed the radar: rdar://34460614

Any assistance to address the problem will be very appreciated.