Admin widget ‘+’ button missing on mobile view

[moeinomidii]

Summary

In mobile view of Django admin, the SortedManyToManyField widget does not display the “+” button
used to add new related objects inline.

Steps to reproduce

1. Open Django admin on mobile (or simulate with browser dev tools).
2. Navigate to a model using SortedManyToManyField.
3. Observe that the “+” button is missing.

Expected behavior

The “+” button should be visible and functional on mobile, just like desktop.

Notes

Tested on Django 4.x with default admin theme. The issue appears to be layout-related.