The critical latent bug Stage 3 introduced: per-slot output names mean a 2nd
exclusive session's other_enabled_outputs() (which disabled 'everything not named
Virtual-punktfunk') would black out the 1st session's Virtual-punktfunk-<id>
output. Fix: recognise the whole managed group by the shared Virtual-punktfunk
prefix — exclusive now disables only NON-managed outputs (bootstrap/physical),
never a group sibling. Plus first-slot-wins for the group primary
(a_managed_output_is_primary): a later session joins as a secondary monitor of the
shared desktop instead of stealing the shell off the first. Unit-tested.
Start of Stage 5 (§6A many-clients-one-desktop). Remaining: Mutter/wlroots
group-aware analogues, layout (auto-row/manual + /display/layout + console),
per-group topology restore, gamescope groups.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
enricobuehler
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