### 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
if (!scr.is_valid()) {
				continue;
			}
			if (!edit(scr, false)) {
				continue;
			}
		} else {
			Error error;
			Ref<TextFile> text_file = _load_text_file(path, &error);
			if (error != OK || !text_file.is_valid()) {
				continue;
			}
			if (!edit(text_file, false)) {
				continue;
			}
		}
		if (!script_info.is_empty()) {
			ScriptEditorBase *se = Object::cast_to<ScriptEditorBase>(tab_container->get_tab_control(tab_container->get_tab_count() - 1));
			if (se) {
				se->set_edit_state(script_info["state"]);
			}
		}
	}
	for (int i = 0; i < helps.size(); i++) {
		String path = helps[i];
		if (path.is_empty()) { 
			continue;
		}
		_help_class_open(path);
	}