diff --git a/customize.dist/src/less2/include/alertify.less b/customize.dist/src/less2/include/alertify.less
index d905f6e3c..ff4a2abec 100644
--- a/customize.dist/src/less2/include/alertify.less
+++ b/customize.dist/src/less2/include/alertify.less
@@ -94,6 +94,7 @@
                 background-color: @alertify-dialog-bg;
                 &.half {
                     width: 50%;
+                    max-width: 50%;
                     @media (max-width: @browser_media-medium-screen) {
                         width: 100%;
                     }