### 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 ret = "Unnamed";
	GDVIRTUAL_CALL(_get_name, ret);
	return ret;
}
PackedStringArray EditorSyntaxHighlighter::_get_supported_languages() const {
	PackedStringArray ret;
	GDVIRTUAL_CALL(_get_supported_languages, ret);
	return ret;
}
Ref<EditorSyntaxHighlighter> EditorSyntaxHighlighter::_create() const {
	Ref<EditorSyntaxHighlighter> syntax_highlighter;
	syntax_highlighter.instantiate();
	if (get_script_instance()) {
		syntax_highlighter->set_script(get_script_instance()->get_script());
	}
	return syntax_highlighter;
}
void EditorSyntaxHighlighter::_bind_methods() {
	ClassDB::bind_method(D_METHOD("_get_edited_resource"), &EditorSyntaxHighlighter::_get_edited_resource);
	GDVIRTUAL_BIND(_get_name)
	GDVIRTUAL_BIND(_get_supported_languages)
}
void EditorStandardSyntaxHighlighter::_update_cache() {