live preview: Re-enable moving and resizing when no layout is in sight

Allow moving and resizing of elements provided:

 * The element is not layout. This approximates
   "fills its parent", which is what we aim for once
   we can query type info rom within the Preview.
 * The element is not *inside* a layout

tools/lsp/preview.rs

@@ -606,6 +606,8 @@ fn set_selections(
     ui: Option<&ui::PreviewUi>,
     main_index: usize,
     is_layout: bool,
+    is_moveable: bool,
+    is_resizable: bool,
     positions: ComponentPositions,
 ) {
     let Some(ui) = ui else {
@@ -634,8 +636,8 @@ fn set_selections(
             y: g.origin.y,
             border_color: if i == main_index { border_color } else { secondary_border_color },
             is_primary: i == main_index,
-            is_moveable: false,
-            is_resizable: false,
+            is_moveable,
+            is_resizable,
         })
         .collect::<Vec<_>>();
     let model = Rc::new(slint::VecModel::from(values));
@@ -647,13 +649,21 @@ fn set_selected_element(
     positions: slint_interpreter::highlight::ComponentPositions,
     notify_editor_about_selection_after_update: bool,
 ) {
+    let (is_layout, is_in_layout) = selection
+        .as_ref()
+        .and_then(|s| s.as_element_node())
+        .map(|en| (en.is_layout(), element_selection::is_element_node_in_layout(&en)))
+        .unwrap_or((false, false));
+
     PREVIEW_STATE.with(move |preview_state| {
         let mut preview_state = preview_state.borrow_mut();
 
         set_selections(
             preview_state.ui.as_ref(),
             selection.as_ref().map(|s| s.instance_index).unwrap_or_default(),
-            selection.as_ref().map(|s| s.is_layout).unwrap_or_default(),
+            is_layout,
+            !is_in_layout && !is_layout,
+            !is_in_layout && !is_layout,
             positions,
         );
 

tools/lsp/preview/element_selection.rs

@@ -392,6 +392,29 @@ pub fn select_element_at(x: f32, y: f32, enter_component: bool) {
     }
 }
 
+pub fn is_element_node_in_layout(element: &ElementRcNode) -> bool {
+    if element.debug_index > 0 {
+        // If we are not the first node, then we might have been inlined right
+        // after a layout managing us
+        element
+            .element
+            .borrow()
+            .debug
+            .get(element.debug_index - 1)
+            .map(|d| d.1.is_some())
+            .unwrap_or_default()
+    } else {
+        // If we are the first node, then we might be a child of a layout stored
+        // in the last node of our parent element.
+        let Some(parent) = i_slint_compiler::object_tree::find_parent_element(&element.element)
+        else {
+            return false;
+        };
+        let r = parent.borrow().debug.last().map(|d| d.1.is_some()).unwrap_or_default();
+        r
+    }
+}
+
 pub fn select_element_behind(x: f32, y: f32, enter_component: bool, reverse: bool) {
     let Some(component_instance) = super::component_instance() else {
         return;