CSS fixes for "Grid" example (#2753)

examples/grid/style.css

@@ -16,7 +16,8 @@ th {
   cursor: pointer;
   -webkit-user-select: none;
   -moz-user-select: none;
-  -user-select: none;
+  -ms-user-select: none;
+  user-select: none;
 }
 
 td {
@@ -55,4 +56,4 @@ th.active .arrow {
   border-left: 4px solid transparent;
   border-right: 4px solid transparent;
   border-top: 4px solid #fff;
-}
+}