### 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
script_back->set_icon(get_theme_icon(SNAME("Back"), SNAME("EditorIcons")));
			}
			members_overview_alphabeta_sort_button->set_icon(get_theme_icon(SNAME("Sort"), SNAME("EditorIcons")));
			filter_scripts->set_right_icon(get_theme_icon(SNAME("Search"), SNAME("EditorIcons")));
			filter_methods->set_right_icon(get_theme_icon(SNAME("Search"), SNAME("EditorIcons")));
			filename->add_theme_style_override("normal", EditorNode::get_singleton()->get_gui_base()->get_theme_stylebox(SNAME("normal"), SNAME("LineEdit")));
			recent_scripts->reset_size();
			if (is_inside_tree()) {
				_update_script_colors();
				_update_script_names();
			}
		} break;
		case NOTIFICATION_READY: {
			get_tree()->connect("tree_changed", callable_mp(this, &ScriptEditor::_tree_changed));
			InspectorDock::get_singleton()->connect("request_help", callable_mp(this, &ScriptEditor::_help_class_open));
			EditorNode::get_singleton()->connect("request_help_search", callable_mp(this, &ScriptEditor::_help_search));
		} break;
		case NOTIFICATION_EXIT_TREE: {
			EditorNode::get_singleton()->disconnect("stop_pressed", callable_mp(this, &ScriptEditor::_editor_stop));
		} break;
		case NOTIFICATION_APPLICATION_FOCUS_IN: {
			_test_script_times_on_disk();
			_update_modified_scripts_for_external_editor();
		} break;
		case CanvasItem::NOTIFICATION_VISIBILITY_CHANGED: {
			if (is_visible()) {
				find_in_files_button->show();
			} else {
				if (find_in_files->is_visible_in_tree()) {
					EditorNode::get_singleton()->hide_bottom_panel();