Index: branches/RC/core/admin_templates/js/catalog.js
===================================================================
diff -u -N -r11546 -r11610
--- branches/RC/core/admin_templates/js/catalog.js	(.../catalog.js)	(revision 11546)
+++ branches/RC/core/admin_templates/js/catalog.js	(.../catalog.js)	(revision 11610)
@@ -224,8 +224,8 @@
 		return false;
 	}
 
-	if (!isset($prefix) || $prefix == '') {
-		// prefix not given OR empty prefix
+	if (!isset($prefix) || $prefix == '' || this.queryTabRegistry('prefix', $prefix, 'prefix') === false) {
+		// prefix not given OR empty prefix OR non-existing tab
 		$prefix = this.ActivePrefix;
 	}