Kristiyan Kostadinov

The code LGTM, but one of the CI checks is failing. You can run `yarn approve-api button` and commit the changed file to fix it.

I couldn't reproduce it against any of the examples [from the docs](https://material.angular.io/cdk/drag-drop/overview), but I'm not sure I understand the instructions. At step 2 am I supposed to move one item,...

I see. The reason why it currently works this way is that it would look weird if we snapped it back into the initial list, because there's nothing taking up...

Can you try it with the latest version of Material? I wasn't able to reproduce it here: https://material.angular.io/components/expansion/overview

Closing the issue since I wasn't able to reproduce it and there hasn't been a response.

I don't see any paint flashing issues either and as mentioned above, the multiple change detections are because we manage the arrow animations inside the `NgZone` which fires off several...

I think that we talked through this over DM at some point. The fix is correct, but it ended up breaking internally because apps were projecting all sorts of unrelated...

This looks like an issue specifically when the tabs are nested inside of a `mat-card`, because outside it works as expected.

As far as I can tell, there's no case where `BreakpointObserver.observe` would return `undefined`. Is it possible that you're mocking out the `BreakpointObserver` in your tests?

We can't do much about what `ng-mocks` is stubbing out the service with. Even if we added a null check, what's to say that some other app won't mock it...