3.1.3

Fix

In split view, the active-pane outline could render as a full-width amber bar across the top of the window instead of marking a single pane. It was targeting the wrong element – the deck tab that sits behind the split and spans the full width – rather than the visible split panes. The outline now follows the pane that holds focus and clears when you switch away from the split.

A brief grey outline may still appear right after switching to a split tab, before you click a pane: that one is Firefox's own native marker, and FoxOne's amber takes over the moment you click in.