### 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
Ref<TextFile> sqscr = p_text_file;
	ERR_FAIL_COND_V(sqscr.is_null(), ERR_INVALID_PARAMETER);
	String source = sqscr->get_text();
	Error err;
	{
		Ref<FileAccess> file = FileAccess::open(p_path, FileAccess::WRITE, &err);
		ERR_FAIL_COND_V_MSG(err, err, "Cannot save text file '" + p_path + "'.");
		file->store_string(source);
		if (file->get_error() != OK && file->get_error() != ERR_FILE_EOF) {
			return ERR_CANT_CREATE;
		}
	}
	if (ResourceSaver::get_timestamp_on_save()) {
		p_text_file->set_last_modified_time(FileAccess::get_modified_time(p_path));
	}
	_res_saved_callback(sqscr);
	return OK;
}
bool ScriptEditor::edit(const Ref<Resource> &p_resource, int p_line, int p_col, bool p_grab_focus) {