That sounds like 1Paswsword Android app is marking its buffers as secure output only.
Visualizing those buffers as black on non secure displays is a feature.

Can you verify that taking a screenshot of that app on the embedded display also produces a black quad? If that's the case, this is working as intended.

@1: Yeah, I've confined that it's also a black box on a screenshot.

Even if this is working as intended, it still seems sub-optimal.  I could imagine 1Password wanting to avoid screen captures and the like, but it seems really non-ideal that it doesn't show up on my external monitor...  Is there some other mode that they should be using?

I don't think we have anything better than that on ARC++ right now.

An external display without HDCP is as easy to capture as taking a screenshot. Why would they want to prevent it to show up in a screenshot and not on an external monitor?

The situation might improve once we get HDCP support.

I'd say this is working as intended.
We might want to talk with ddorwin@ regarding an alternative mode, since he originally drafted and then agreed with the current secure output design for ARC++.

Yes, this is WAI per the Android APIs.