### Godot version

3.5.1mono

### System information

windows10

### Issue description

Error message
 scene/main/node.cpp:1362 - Index p_index = 0 is out of bounds (data.children.size() = 0).
 scene/main/node.cpp:397 - Parameter "p_child" is null.
 scene/gui/tab_container.cpp:593 - Index p_current = 0 is out of bounds (get_tab_count() = 0).
See "Steps to reproduce for details"

### Steps to reproduce

Set an external text editor
Create a script
Drop the script to the built-in text editor like this image:
![image](https://user-images.githubusercontent.com/119792950/209504041-039f2620-5e42-4c0f-8c41-cd24486fb3d2.png)
And got error message:
 scene/main/node.cpp:1362 - Index p_index = 0 is out of bounds (data.children.size() = 0).
 scene/main/node.cpp:397 - Parameter "p_child" is null.
 scene/gui/tab_container.cpp:593 - Index p_current = 0 is out of bounds (get_tab_count() = 0).

### Minimal reproduction project

An empty project
if (se || eh) {
			int new_index = 0;
			if (script_list->get_item_count() > 0) {
				new_index = script_list->get_item_metadata(script_list->get_item_at_position(p_point));
			}
			tab_container->move_child(node, new_index);
			tab_container->set_current_tab(new_index);
			_update_script_names();
		}
	}
	if (String(d["type"]) == "files") {
		Vector<String> files = d["files"];
		int new_index = 0;
		if (script_list->get_item_count() > 0) {
			new_index = script_list->get_item_metadata(script_list->get_item_at_position(p_point));
		}
		int num_tabs_before = tab_container->get_tab_count();
		for (int i = 0; i < files.size(); i++) {
			String file = files[i];
			if (file.is_empty() || !FileAccess::exists(file)) {
				continue;
			}
			if (!ResourceLoader::exists(file, "Script") && !textfile_extensions.has(file.get_extension())) {
				continue;
			}
			Ref<Resource> res = open_file(file);
			if (res.is_valid()) {
				if (tab_container->get_tab_count() > num_tabs_before) {
					tab_container->move_child(tab_container->get_tab_control(tab_container->get_tab_count() - 1), new_index);
					num_tabs_before = tab_container->get_tab_count();