### 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
_copy_script_path();
			} break;
			case SHOW_IN_FILE_SYSTEM: {
				const Ref<Resource> scr = current->get_edited_resource();
				String path = scr->get_path();
				if (!path.is_empty()) {
					if (scr->is_built_in()) {
						path = path.get_slice("::", 0); 
					}
					FileSystemDock *file_system_dock = FileSystemDock::get_singleton();
					file_system_dock->navigate_to_path(path);
					
					TabContainer *dock_tab_container = (TabContainer *)file_system_dock->get_parent_control();
					dock_tab_container->set_current_tab(dock_tab_container->get_tab_idx_from_control(file_system_dock));
				}
			} 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(current, tab_container->get_current_tab() - 1);
					tab_container->set_current_tab(tab_container->get_current_tab());
					_update_script_names();