Restore custom height for projects dropdown

app/assets/stylesheets/framework/dropdowns.scss

@@ -30,7 +30,7 @@
     @include set-visible;
     min-height: $dropdown-min-height;
     max-height: $dropdown-max-height;
-    overflow: auto;
+    overflow-y: auto;
 
     @media (max-width: $screen-xs-max) {
       width: 100%;

app/assets/stylesheets/framework/header.scss

@@ -303,6 +303,8 @@
 
   .projects-dropdown-menu {
     padding: 0;
+    overflow-y: initial;
+    max-height: initial;
   }
 
   .dropdown-chevron {