Bulk update sidebar UI polish

app/assets/javascripts/issuable_bulk_update_sidebar.js

@@ -86,10 +86,23 @@ export default class IssuableBulkUpdateSidebar {
     this.toggleCheckboxDisplay(enable);
 
     if (enable) {
+      this.initAffix();
       SidebarHeightManager.init();
     }
   }
 
+  initAffix() {
+    if (!this.$sidebar.hasClass('affix-top')) {
+      const offsetTop = $('.scrolling-tabs-container').outerHeight() + $('.sub-nav-scroll').outerHeight();
+
+      this.$sidebar.affix({
+        offset: {
+          top: offsetTop,
+        },
+      });
+    }
+  }
+
   updateSelectedIssuableIds() {
     this.$issuableIdsInput.val(IssuableBulkUpdateSidebar.getCheckedIssueIds());
   }

app/assets/stylesheets/framework/nav.scss

@@ -190,14 +190,6 @@
       display: none;
     }
 
-    .btn,
-    .dropdown,
-    .dropdown-toggle,
-    input,
-    form {
-      height: 35px;
-    }
-
     input {
       display: inline-block;
       position: relative;

app/assets/stylesheets/framework/sidebar.scss

@@ -92,7 +92,6 @@
 @mixin maintain-sidebar-dimensions {
   display: block;
   width: $gutter-width;
-  padding: 10px 0;
 }
 
 .issues-bulk-update.right-sidebar {
@@ -104,6 +103,15 @@
   &.right-sidebar-expanded {
     @include maintain-sidebar-dimensions;
     width: $gutter-width;
+
+    .issuable-sidebar-header {
+      // matches `.top-area .nav-controls` for issuable index pages
+      padding: 11px 0;
+    }
+
+    .block:last-of-type {
+      border: none;
+    }
   }
 
   &.right-sidebar-collapsed {

app/assets/stylesheets/new_sidebar.scss

@@ -23,6 +23,10 @@ $new-sidebar-width: 220px;
     position: fixed;
     height: 100%;
   }
+
+  .issues-bulk-update.right-sidebar.right-sidebar-expanded .issuable-sidebar-header {
+    padding: 10px 0 15px;
+  }
 }
 
 .context-header {

app/views/shared/issuable/_bulk_update_sidebar.html.haml

 - type = local_assigns.fetch(:type)
 
-%aside.issues-bulk-update.js-right-sidebar.right-sidebar.affix-top{ data: { "offset-top" => "50", "spy" => "affix" }, "aria-live" => "polite" }
+%aside.issues-bulk-update.js-right-sidebar.right-sidebar{ "aria-live" => "polite", data: { 'signed-in': current_user.present? } }
   .issuable-sidebar.hidden
     = form_tag [:bulk_update, @project.namespace.becomes(Namespace), @project, type], method: :post, class: "bulk-update"  do
-      .block
+      .block.issuable-sidebar-header
         .filter-item.inline.update-issues-btn.pull-left
           = button_tag "Update all", class: "btn update-selected-issues btn-info", disabled: true
         = button_tag "Cancel", class: "btn btn-default js-bulk-update-menu-hide pull-right"