Ticket #27620: 27620.patch

src/wp-admin/js/customize-controls.js

@@ -198 +198 @@
                                 init: function() {
                                         var fallback, button;
 
-                                        if ( this.supports.dragdrop )
+                                        if ( this.supported )
                                                 return;
 
                                         // Maintain references while wrapping the fallback button.
                                         fallback = control.container.find( '.upload-fallback' );
                                         button   = fallback.children().detach();
 
+                                        this.dropzone.hide();
                                         this.browser.detach().empty().append( button );
                                         fallback.append( this.browser ).show();
                                 }