Fixed tree menu positioning

Change-Id: I28cf53df1cfe60732da73af43adab998220c0f4a
diff --git a/dev/scss/main/buttongroup.scss b/dev/scss/main/buttongroup.scss
index 0b89b11..269b5c1 100644
--- a/dev/scss/main/buttongroup.scss
+++ b/dev/scss/main/buttongroup.scss
@@ -77,9 +77,8 @@
 }
 
 
-ul.button-group-list {
+ul.menu.button-group-list {
   border-top-right-radius: 8px;
-  z-index: 150;
   font-size: 10pt;
   position: fixed;
   left: 0;