Quick Fix for Upload breakage after WP 5.3

For anyone who needs to keep this working temporarily until they find a replacement, here are the TWO lines of code that are causing the upload tab to break in WordPress 5.3+

File: enhanced-media-library/js/eml-media-views.js

Comment out or delete lines 1129 and 1130:

this.attachments.listenTo( this.controller, 'attachment:keydown:arrow',     this.attachments.arrowEvent );
this.attachments.listenTo( this.controller, 'attachment:details:shift-tab', this.attachments.restoreFocus );

That’s it. Removing those restores the upload tab functionality.

Of course, don’t keep using an abandoned plug-in, but this may keep you up and running until you find a new viable option.