Merge branch 'b13139-sticky' into 'develop'

added z-index

See merge request !360

less/qfq-bs.css.less

@@ -1233,6 +1233,7 @@ legend {
   position: -webkit-sticky; /* Safari */
   position: sticky;
   top: 0;
+  z-index: 10;
 }
 
 thead.qfq-sticky th, thead.qfq-sticky td {