### 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
} else {
					num_chars++;
				}
			}
		}
		
		if (!has_file_flag) {
			args.push_back(script_path);
		}
		Error err = OS::get_singleton()->create_process(path, args);
		if (err == OK) {
			return false;
		}
		WARN_PRINT("Couldn't open external text editor, using internal");
	}
	for (int i = 0; i < tab_container->get_tab_count(); i++) {
		ScriptEditorBase *se = Object::cast_to<ScriptEditorBase>(tab_container->get_tab_control(i));
		if (!se) {
			continue;
		}
		if ((scr != nullptr && se->get_edited_resource() == p_resource) || se->get_edited_resource()->get_path() == p_resource->get_path()) {
			if (should_open) {
				se->enable_editor(this);
				if (tab_container->get_current_tab() != i) {
					_go_to_tab(i);
					_update_script_names();
				}
				if (is_visible_in_tree()) {
					se->ensure_focus();
				}