Legacy setup-wizard registers a label-less submenu under Appearance (blank menu entry)

[georgeolaru]

Summary

The legacy setup wizard registers a label-less submenu under Appearance, so a blank/empty menu line appears under Appearance → (Themes, Editor, …, [blank], Install Plugins).

Root cause

admin/class-pixelgrade_assistant-setup_wizard.php:63

add_submenu_page( 'themes.php', '', '', 'manage_options', 'pixelgrade_assistant-setup-wizard', null );

Parenting the route to themes.php with empty title/menu-title makes WordPress render a blank submenu item. The wizard route is intentionally kept for compatibility — tests/admin-menu-retirement-test.php:111 pins the slug pixelgrade_assistant-setup-wizard as stable — so the goal is to keep the route reachable without the blank menu entry.

Fix

Register the route as a hidden page (e.g. add_submenu_page( null, … ), or unset it from $submenu after registration) so the slug stays valid for redirects/links but no empty line shows under Appearance. Keep the retirement test green (slug unchanged).

Repro

pixelgrade-integrated-check (http://localhost:8889) → Appearance submenu shows a blank entry between Fonts/Widgets and Install Plugins.

Severity

Minor / polish.