Text: duplicate during a text edit leaves no keyframe or mask vertex selected on the original (#2226)

Opening the editor keeps the keyframe and mask-vertex selection as well as the property one,
and Duplicate cleared only the properties. With the copy selected, Clear then deleted a key or
vertex of the original instead of the copy. During an edit the copies now take the selection the
way a click on them does: layer.select's rule, moved into one helper both use. With no edit
open, Duplicate's selection is unchanged.

crates/engine/src/cmd/edit.rs

@@ -151,11 +151,13 @@ fn duplicate(s: &mut Session, p: &Value) -> Result<Value> {
         }
         relink_copies(comp, &map);
         proj.next_id = next;
-        st.selected_layers = created.clone();
-        // The property selection the edit kept was passed over above and belongs to the
-        // originals: left in place, the next Duplicate or Clear would act on it, not the copies.
+        // The property, keyframe and mask-vertex selection the edit kept belongs to the originals;
+        // left in place, the next Duplicate or Clear would act on it, not on the copies. So during
+        // an edit the copies take the selection the way a click on them would.
         if editing {
-            st.selected_props.clear();
+            super::layer::select_only(st, created.clone());
+        } else {
+            st.selected_layers = created.clone();
         }
         Ok(created)
     })?;

crates/engine/src/cmd/layer.rs

@@ -28,6 +28,7 @@ pub(crate) use create::{color_p, index_p, insert_layer, insert_layer_at, place,
 pub(crate) use parent::parent_fixes;
 use parent::set_parent;
 use replace::{has_replace_source, replace_source};
+pub(crate) use select::select_only;
 use select::{select, select_next, select_prev, select_step};
 use switches::{blend, rename, set_comment, set_switch, track_matte};
 use timing::{arrange, move_frames, precompose, slip, timing};

crates/engine/src/cmd/layer/select.rs

@@ -25,15 +25,21 @@ pub(super) fn select(s: &mut Session, p: &Value) -> Result<Value> {
             }
         }
     } else {
-        s.state.selected_layers = ids;
-        s.state.selected_props.clear();
-        s.state.selected_keys.clear();
-        let keep = s.state.selected_layers.clone();
-        s.state.selected_vertices.retain(|v| keep.contains(&v.layer));
+        select_only(&mut s.state, ids);
     }
     Ok(json!(s.state.selected_layers.iter().map(|l| l.0).collect::<Vec<_>>()))
 }
 
+/// Make `ids` the whole layer selection, as a plain click on them does: no property or keyframe
+/// stays selected, and mask vertices stay selected only on layers that are still selected.
+pub(crate) fn select_only(st: &mut crate::EditorState, ids: Vec<LayerId>) {
+    st.selected_layers = ids;
+    st.selected_props.clear();
+    st.selected_keys.clear();
+    let keep = st.selected_layers.clone();
+    st.selected_vertices.retain(|v| keep.contains(&v.layer));
+}
+
 pub(super) fn select_step(s: &mut Session, p: &Value, dir: i64) -> Result<Value> {
     let comp = s.active_comp().ok_or(EngineError::NoComp)?;
     if comp.layers.is_empty() {