diff --git a/src/sao.less b/src/sao.less
index 0c8c1727ec..d792a197ce 100644
--- a/src/sao.less
+++ b/src/sao.less
@@ -149,6 +149,9 @@ button {
             height: 1em;
         }
     }
+    & .form-many2one > .input-group {
+        width: 100%;
+    }
     & td.form-one2many, td.form-many2many {
         vertical-align: top;
     }