Layers: Merge Selected keeps to the highlighted layers, as documented (#2383)

Reverts the fallback that merged the layers of art selected on the canvas when no
layer row is highlighted: Illustrator's Merge Selected merges the highlighted rows
into the last one highlighted.

crates/engine/src/cmd/layerpanel.rs

@@ -263,22 +263,13 @@ fn merge_into(d: &mut Document, into: NodeId, others: &[NodeId]) -> Result<()> {
 
 fn merge(s: &mut Session, p: &Value) -> Result<Value> {
     const C: &str = "layer.merge";
-    let mut ids = rows_param(s, p, C)?;
+    let ids = rows_param(s, p, C)?;
     let st = s.doc()?;
     let d = &st.doc;
-    // Nothing named or highlighted, but art selected on the canvas in several layers (Select All):
-    // merge those layers (#2383).
-    if p.get("ids").is_none() && p.get("id").is_none() && st.highlighted_rows().is_empty() {
-        let held: HashSet<NodeId> = st.selection.objects.iter().filter_map(|o| d.layer_of(*o)).collect();
-        let layers: Vec<NodeId> = d.layers.iter().map(|l| l.id).filter(|l| held.contains(l)).collect();
-        if layers.len() >= 2 {
-            ids = layers;
-        }
-    }
     let mut seen = HashSet::new();
     let ids: Vec<NodeId> = ids.into_iter().filter(|id| d.node(*id).is_some() && seen.insert(*id)).collect();
     if ids.len() < 2 {
-        return Err(bad(C, "highlight two or more rows to merge, or select art in two or more layers"));
+        return Err(bad(C, "highlight two or more rows to merge"));
     }
     // The last highlighted layer that is not inside another highlighted row: with a layer and its
     // sublayer both highlighted (Select All in the panel), the sublayer travels with its layer

crates/engine/src/tests_layers.rs

@@ -625,24 +625,6 @@ fn merge_selected_with_all_layer_rows_highlighted_merges_into_the_last_top_level
     }
 }
 
-/// Merge Selected with no highlighted rows but art selected in several layers (Select All on the
-/// canvas) merges those layers; art in one layer still asks for rows (#2383).
-#[test]
-fn merge_selected_with_art_selected_in_several_layers_merges_those_layers() {
-    let mut s = session();
-    let a = rect(&mut s, 0.0);
-    run(&mut s, "layer.new", json!({"top": true}));
-    let b = rect(&mut s, 100.0);
-    run(&mut s, "select.set", json!({"ids": [b.0]}));
-    run(&mut s, "layer.highlight", json!({"ids": []}));
-    assert!(s.execute("layer.merge", &json!({})).is_err());
-    run(&mut s, "select.set", json!({"ids": [a.0, b.0]}));
-    let into = id(&run(&mut s, "layer.merge", json!({})));
-    let st = s.doc().unwrap();
-    assert_eq!(st.doc.layers.len(), 1);
-    assert!(st.doc.layer_of(a) == Some(into) && st.doc.layer_of(b) == Some(into));
-}
-
 /// Collect in New Layer puts the new layer beside the topmost row when that row is directly in a
 /// layer, and on top of the layer holding its group when it is in a group. When that row is in a
 /// hidden or locked layer, the selected art it collects from another layer is deselected, the key

crates/ui-egui/src/panels/layers.rs

@@ -1461,8 +1461,6 @@ pub fn menu(app: &mut VectorcraftApp, ui: &mut Ui) {
     let rows = st.highlighted_rows();
     let current = st.current_layer();
     let has_sel = !st.selection.is_empty();
-    // How many top-level layers hold the selected art: Merge Selected merges them.
-    let art_layers = st.selection.objects.iter().filter_map(|o| doc.layer_of(*o)).collect::<HashSet<_>>().len();
     let isolated = st.isolation.is_some();
     let targets: Vec<NodeId> = if rows.is_empty() { current.into_iter().collect() } else { rows.clone() };
     let one_container = match targets.as_slice() {
@@ -1500,7 +1498,7 @@ pub fn menu(app: &mut VectorcraftApp, ui: &mut Ui) {
         None,
         Some(("Locate Object", "layer.locate", json!({}), has_sel, false)),
         None,
-        Some(("Merge Selected", "layer.merge", json!({}), rows.len() >= 2 || (rows.is_empty() && art_layers >= 2), false)),
+        Some(("Merge Selected", "layer.merge", json!({}), rows.len() >= 2, false)),
         Some(("Flatten Artwork", "layer.flatten", json!({}), true, false)),
         Some(("Collect in New Layer", "layer.collectInNew", json!({}), !rows.is_empty() || has_sel, false)),
         // Sentinel: rendered as Collect for Export › As Single / As Multiple (assets.add).