Specify focused removal semantics and document diagram shortcuts

docs/language.rst

@@ -2083,6 +2083,46 @@ exchanges it references. Cross-layer counterparts are not owned descendants.
 Text edits describe a complete candidate and must remove or repair dependencies
 explicitly before Apply succeeds.
 
+8.1. Focused diagram removal
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Delete is scoped to the focused diagram and the exact visible selection.
+Text fields retain their own Delete behavior; diagram shortcuts MUST NOT apply
+pending property, source or behavior drafts. Keyboard traversal retires diagram
+input admission before subsequent keys in the same event batch are processed.
+Active placement, creation, connection, reorder and pan gestures do not authorize
+removal. A stale document, revision, owner or selection MUST NOT redirect removal.
+
+For an explicit architecture or state placement, Delete removes that placement
+only. The semantic element and its placements in other views remain. Shift+Delete
+requests confirmed deletion of the semantic element, including when selection
+originated from Placement properties. A selected architecture route bend takes
+priority: plain Delete removes the bend without removing its edge.
+
+A visible relation with no placement, including a state action or internal
+transition row, uses confirmed relation deletion for either key. States and
+referenced Activity/Function definitions remain. Hidden or collapsed rows are
+not keyboard deletion targets.
+
+Process and scenario projections have no independent occurrence placements.
+Delete and Shift+Delete request confirmed removal of the selected occurrence,
+participant or maintained link. A link's endpoints and outbound reusable
+definitions are preserved. Removing a fragment or branch removes its owned
+subtree. Removing a scenario participant preserves its represented element and
+retains occurrences with affected participant references cleared; resulting
+incomplete references remain visible for repair. The modeled scenario Delete
+message is a separate domain event and is not this editing shortcut.
+
+A qualified selection inside an expanded reusable process MUST NOT silently
+delete the outer reference or shared definition item. The editor directs the
+user to open the definition or explicitly select the outer reference.
+
+Confirmation identifies the captured object and removal effect. Cancel and
+Escape preserve model, source and history. A confirmation token belongs to one
+dialog; changes to its document, revision, owner or selected identity invalidate
+it. Accepted deletion uses one ordinary model/source transaction, and Undo
+restores the exact complete accepted source bundle and model.
+
 9. Persistence and explicit migration
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