Shouldn't load on widgets.php

When using the admin_footer hook, the widget metabox gets duplicated and shows the entire metabox in the admin_footer as well as the admin_footer sidebar.

I think doing avoiding the widgets page all together is probably a good idea to avoid breaking the page completly which would require manually disabling the plugin.

Anyway, this is a great idea for a plugin.

https://wordpress.org/plugins/magic-widgets/