Thanks a lot for the reply. I filed a feedback with a sample project and screen capture FB11745181.
In the sample project I used a plain UIScrollview. Tabbing into it doesn't work. After fiddling with the quick sample I noticed that arrow key scrolling doesn't work at all (even when clicking on the scroll view).
In the app I'm actually working on I'm using a WKWebView which does have arrow key scrolling implemented but was requiring at least a mouse click on the web view before it started working (couldn't tab in).
It's hard to say what might be happening without a sample project, but — on the Mac — keyboard navigation is going to change first-responder, not focus.
That's what I thought. I fiddled with calls to -becomeFirstResponder with no luck (on the view controller and on the web view itself).
Subclassing and returning YES from -canBecomeFocused on the view is all I needed to do to get focus to move over with the tab key, without messing with the responder chain at all.
But I also needed to implement my own key commands to actually do the scrolling now because the default web view ones don't work after these overrides.