Plasma 6.2.5 keeps a panel on a screen number and never moves one whose
number is past the screen count, so a taskbar saved on a spare output
(#18, lastScreen=8 with three screens) or on a screen a smaller layout
dropped stayed hidden. Before Plasma starts, session/fix-panels.py moves
such a panel and its tray's containment to screen 0 (the primary),
keeping its widgets, unless screen 0 already has a panel on that edge.
doctor.sh checks the panels' screens, and report.sh lists them with the
live outputs and panels.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>