Drop the fullscreen panel's whole-box no-drag: it swallowed the strips'
blank-run window drag and made no-drag the steady state, turning the
open/close app-region nudge into a computed-value no-op (electron#32341)
exactly when a hidden panel opens straight into fullscreen. The panel now
declares no steady-state app-region in either presentation, and ui-dockkit
subtracts the one box base.css never matches — the plain-div split divider —
alongside tabs, strip-end chrome, and pane bodies. New specs pin both
contracts against the stylesheets on disk.
Seed sidebar default pages lazily on expansion, scope page-tab dedupe
to the target pane, let a sole tab split its own pane with a factory
backfill, close menus when focus enters a sandboxed iframe, and pin the
code preview copy banner while unifying its background with the pane.
Chip capsules with scroll fades and live titles, drop-zone hint cards, the
canCloseTab control policy with the quiet lone chip and self-dismissing empty
menu, and a room reading that stays independent of hidden split controls.
Yif