Bonsai: duplicate-drawing share toggle only preserves already-shared annotations

The "Share Annotations" toggle shared every manual annotation on the source
drawing, which surprised users - a note unique to that drawing shouldn't
silently become a shared element on the copy.

It now preserves existing sharing only: an annotation already assigned to
more than one drawing stays shared with the duplicate, while annotations
unique to this drawing (and auto-generated tags) are still duplicated into
independent copies. The toggle is renamed "Keep Shared Annotations Shared"
to match.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/bonsai/bonsai/bim/module/drawing/operator.py

@@ -203,10 +203,11 @@ class DuplicateDrawing(bpy.types.Operator, tool.Ifc.Operator):
     drawing: bpy.props.IntProperty()
     should_duplicate_annotations: bpy.props.BoolProperty(name="Should Duplicate Annotations", default=False)
     share_annotations: bpy.props.BoolProperty(
-        name="Share Annotations",
+        name="Keep Shared Annotations Shared",
         description=(
-            "Assign the same annotations to the new drawing (shared - editing one updates both) "
-            "instead of creating independent copies. Auto-generated tags are always copied"
+            "Annotations already shared across multiple drawings stay shared with the new drawing "
+            "(editing one updates both) instead of being copied. Annotations unique to this drawing "
+            "are still duplicated"
         ),
         default=False,
     )

src/bonsai/bonsai/core/drawing.py

@@ -370,12 +370,16 @@ def duplicate_drawing(
     if should_duplicate_annotations:
         source_annotations = [a for a in drawing_tool.get_group_elements(group) if a != drawing]
         if share_annotations:
-            # Share manual annotations with the new drawing (multi-group membership):
-            # the same entity now belongs to both drawings' groups, so edits propagate.
-            # Auto-generated tags (grid/section/storey) can't be shared - they are
-            # regenerated per drawing - so they are still duplicated.
-            to_share = [a for a in source_annotations if not drawing_tool.is_auto_annotation(a)]
-            to_duplicate = [a for a in source_annotations if drawing_tool.is_auto_annotation(a)]
+            # Preserve existing sharing: an annotation that already appears on more
+            # than one drawing stays shared with the duplicate (the same entity is
+            # added to the new drawing's group, so edits keep propagating). Annotations
+            # unique to this drawing - and auto-generated tags - are duplicated as usual.
+            to_share = [
+                a
+                for a in source_annotations
+                if not drawing_tool.is_auto_annotation(a) and len(drawing_tool.get_annotation_drawings(a)) > 1
+            ]
+            to_duplicate = [a for a in source_annotations if a not in to_share]
             if to_share:
                 ifc.run("group.assign_group", group=new_group, products=to_share)
         else: