Correct z-index for title dropdown in sub-menu and dropdown hover header on scroll

client/src/sass/bootstrap.scss

@@ -65,7 +65,7 @@ $icon-font-path: '~@neos21/bootstrap3-glyphicons/assets/fonts/';
 
 .list-overflow-menu,
 .parent-entry {
-  z-index: z(header) - 1 !important;
+  z-index: z(menu) - 1 !important;
 }
 
 .btn-group,

client/src/sass/include/_variables.scss

@@ -163,13 +163,13 @@ $zindex: (
   sub-menu        : 12500,
   menu            : 12600,
   search-typeahead: 12650,
-  header          : 12700,
   popover         : 13000,
   tooltip         : 14000,
   loadbar         : 15000,
   modal           : 16000,
   dropdown        : 17000,
   help-popover    : 17000,
+  header          : 17500,
   notification    : 18000,
   hotkeys         : 19000
 );