### Godot version

4.1.1

### System information

linux

### Issue description

![image](https://github.com/godotengine/godot-proposals/assets/71937306/04dcf0e9-1c0d-4a7f-8ca9-827dd281253a)

![image](https://github.com/godotengine/godot-proposals/assets/71937306/aa70e31e-0486-455a-b8b4-7e589ec7b754)

notice how the first option in the list is never aligned with the button that spawned it.

### Steps to reproduce

right click in the FileSystem dock and hover over the `Create New →` option.

### Minimal reproduction project

editor
#include "popup_menu.h"
#include "popup_menu.compat.inc"
#include "core/config/project_settings.h"
#include "core/input/input.h"
#include "core/os/keyboard.h"
#include "core/os/os.h"
#include "core/string/print_string.h"
#include "core/string/translation.h"
#include "scene/gui/menu_bar.h"
#include "scene/theme/theme_db.h"
String PopupMenu::_get_accel_text(const Item &p_item) const {
	if (p_item.shortcut.is_valid()) {
		return p_item.shortcut->get_as_text();
	} else if (p_item.accel != Key::NONE) {
		return keycode_get_string(p_item.accel);
	}
	return String();
}
Size2 PopupMenu::_get_item_icon_size(int p_idx) const {