### 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
return list_split->is_visible();
}
void ScriptEditor::_menu_option(int p_option) {
	ScriptEditorBase *current = _get_current_editor();
	switch (p_option) {
		case FILE_NEW: {
			script_create_dialog->config("Node", "new_script", false, false);
			script_create_dialog->popup_centered();
		} break;
		case FILE_NEW_TEXTFILE: {
			file_dialog->set_file_mode(EditorFileDialog::FILE_MODE_SAVE_FILE);
			file_dialog->set_access(EditorFileDialog::ACCESS_FILESYSTEM);
			file_dialog_option = FILE_NEW_TEXTFILE;
			file_dialog->clear_filters();
			for (const String &E : textfile_extensions) {
				file_dialog->add_filter("*." + E, E.to_upper());
			}
			file_dialog->popup_file_dialog();
			file_dialog->set_title(TTR("New Text File..."));
			open_textfile_after_create = true;
		} break;
		case FILE_OPEN: {
			file_dialog->set_file_mode(EditorFileDialog::FILE_MODE_OPEN_FILE);
			file_dialog->set_access(EditorFileDialog::ACCESS_FILESYSTEM);
			file_dialog_option = FILE_OPEN;
			List<String> extensions;