The selected segment was an inverted fill — theme foreground behind
surface0 text — which in dark mode dropped a white slab into thin
chrome like the file toolbar, and the fully rounded corners made it
read as a lozenge rather than a tab. It now uses a surface3 fill with
foreground text, and each segment takes the corner radius of the
button at its size tier.
Segments also drop one padding step below the equivalent button. The
gap between segments already supplies the visual padding, so matching
button padding made the track wider than it needed to be and ate the
breathing room around it in a 32px toolbar row.
Selection changes colour only. No weight or size change, so labels
never reflow as you switch segments.
Carries the buttonControlHeight extraction that was already sitting in
control-geometry.ts, since the two files could not be split apart
cleanly for this commit. Its callers stay uncommitted.
Mohamed Boudra
ac6a0afdc7