Fix incorrect hint when drag-and-drop asset into scene

editor/plugins/canvas_item_editor_plugin.cpp

@@ -5504,6 +5504,11 @@ void CanvasItemEditorViewport::_create_preview(const Vector<String> &files) cons
 		Ref<Texture2D> texture = Ref<Texture2D>(Object::cast_to<Texture2D>(*res));
 		Ref<PackedScene> scene = Ref<PackedScene>(Object::cast_to<PackedScene>(*res));
 		if (texture != nullptr || scene != nullptr) {
+			bool root_node_selected = EditorNode::get_singleton()->get_editor_selection()->is_selected(EditorNode::get_singleton()->get_edited_scene());
+			String desc = TTR("Drag and drop to add as child of current scene's root node.") + "\n" + TTR("Hold Ctrl when dropping to add as child of selected node.");
+			if (!root_node_selected) {
+				desc += "\n" + TTR("Hold Shift when dropping to add as sibling of selected node.");
+			}
 			if (texture != nullptr) {
 				Sprite2D *sprite = memnew(Sprite2D);
 				sprite->set_texture(texture);
@@ -5511,14 +5516,15 @@ void CanvasItemEditorViewport::_create_preview(const Vector<String> &files) cons
 				preview_node->add_child(sprite);
 				label->show();
 				label_desc->show();
-				label_desc->set_text(TTR("Drag and drop to add as child of current scene's root node.\nHold Ctrl when dropping to add as child of selected node.\nHold Shift when dropping to add as sibling of selected node.\nHold Alt when dropping to add as a different node type."));
+				desc += "\n" + TTR("Hold Alt when dropping to add as a different node type.");
+				label_desc->set_text(desc);
 			} else {
 				if (scene.is_valid()) {
 					Node *instance = scene->instantiate();
 					if (instance) {
 						preview_node->add_child(instance);
 						label_desc->show();
-						label_desc->set_text(TTR("Drag and drop to add as child of current scene's root node.\nHold Ctrl when dropping to add as child of selected node.\nHold Shift when dropping to add as sibling of selected node."));
+						label_desc->set_text(desc);
 					}
 				}
 			}