Hi Isomorphic,

please see this sample (v12.0p_2019-12-20, also 11.1p, 12.1d) and close all groups from top to bottom by clicking them with the mouse.
Then use up and down keys to navigate between the groups. Only if you are at top and hit up again or are at bottom and hit down again you'll get a visual notification (blue glow) what row you are focusing. Otherwise you can only click right to open the group.
I'd expect this blue glow to be present all the time and to wander with every keypress.

Click image for larger version

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I found this testing this bug report, where it also happens in the reference docs.

Best regards