### 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
String cname = p_desc.get_slice(":", 1);
	if (_help_tab_goto(cname, p_desc)) {
		return;
	}
	EditorHelp *eh = memnew(EditorHelp);
	eh->set_name(cname);
	tab_container->add_child(eh);
	_go_to_tab(tab_container->get_tab_count() - 1);
	eh->go_to_help(p_desc);
	eh->connect("go_to_help", callable_mp(this, &ScriptEditor::_help_class_goto));
	_add_recent_script(eh->get_class());
	_sort_list_on_update = true;
	_update_script_names();
	_save_layout();
	call_deferred("_help_tab_goto", cname, p_desc);
}
bool ScriptEditor::_help_tab_goto(const String &p_name, const String &p_desc) {