### 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
_close_current_tab();
				} break;
				case CLOSE_DOCS: {
					_close_docs_tab();
				} break;
				case CLOSE_OTHER_TABS: {
					_close_other_tabs();
				} break;
				case CLOSE_ALL: {
					_close_all_tabs();
				} break;
				case WINDOW_MOVE_UP: {
					if (tab_container->get_current_tab() > 0) {
						tab_container->move_child(help, tab_container->get_current_tab() - 1);
						tab_container->set_current_tab(tab_container->get_current_tab());
						_update_script_names();
					}
				} break;
				case WINDOW_MOVE_DOWN: {
					if (tab_container->get_current_tab() < tab_container->get_tab_count() - 1) {
						tab_container->move_child(help, tab_container->get_current_tab() + 1);
						tab_container->set_current_tab(tab_container->get_current_tab());
						_update_script_names();
					}
				} break;
			}
		}
	}
}
void ScriptEditor::_theme_option(int p_option) {