fix(core): state order and handling of new trees

core/src/widget/tree.rs

@@ -9,7 +9,7 @@
 
 thread_local! {
     /// A map of named widget states.
 pub static NAMED: std::cell::RefCell<HashMap<Cow<'static, str>, (State, Vec<(usize, Tree)>)>> = std::cell::RefCell::new(HashMap::new());
 }
 
 /// A persistent state widget tree.
@@ -61,7 +61,7 @@
     /// Takes all named widgets from the tree.
     pub fn take_all_named(
         &mut self,
     ) -> HashMap<Cow<'static, str>, (State, Vec<(usize, Tree)>)> {
         let mut named = HashMap::new();
         struct Visit {
             parent: Cow<'static, str>,
@@ -76,7 +76,7 @@
                 let state = mem::replace(&mut tree.state, State::None);
                 let children_count = tree.children.len();
                 let children =
-                    tree.children.iter_mut().rev().enumerate().map(|(i, c)| {
+                    tree.children.iter_mut().enumerate().rev().map(|(i, c)| {
                         if matches!(c.id, Some(Id(Internal::Custom(_, _)))) {
                             (c, None)
                         } else {
@@ -350,7 +350,11 @@
         }
 
         for (new_tree, i) in new_trees {
-            self.children.insert(i, new_tree);
+            if self.children.len() > i {
+                self.children[i] = new_tree;
+            } else {
+                self.children.push(new_tree);
+            }
         }
     }
 }