The Layer Manager already applied colour/linetype/lineweight in bulk;
extend that to the rest:
- Visibility, lock and freeze toggles now act on every selected layer, not
just the clicked row. The clicked row's new state becomes the target for
all. Transparency edits apply to the whole selection too.
- Clicking a linetype/lineweight combo on a row that is already part of a
multi-selection no longer collapses the selection (the whole row is one
mouse_area whose plain-click select would otherwise reset it), so those
edits stay bulk.
- Ctrl/Cmd+A selects every layer row while the Layer Manager is open, and
all drawing objects otherwise.
Two now-unused Scene layer-toggle helpers are removed (the handlers set the
flags directly and bump once).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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