diff --git a/src/messenger/webim/operator/group.php b/src/messenger/webim/operator/group.php
index b4a5af1d..ff8e9ab5 100644
--- a/src/messenger/webim/operator/group.php
+++ b/src/messenger/webim/operator/group.php
@@ -100,9 +100,12 @@ if (isset($_POST['name'])) {
 	if ($email != '' && !is_valid_email($email))
 		$errors[] = wrong_field("form.field.mail");
 
-	if (! preg_match("/^\d{1,9}$/", $weight))
+	if (! preg_match("/^(\d{1,9})?$/", $weight))
 		$errors[] = wrong_field("form.field.groupweight");
 
+	if ($weight == '')
+		$weight = 0;
+
 	if (! $parentgroup)
 		$parentgroup = NULL;