Fixed some styling issues in new list dropdown

app/assets/javascripts/boards/components/new_list_dropdown.js.es6

@@ -23,6 +23,10 @@ $(() => {
 
         return $li.append($a.prepend($labelColor));
       },
+			search: {
+				fields: ['title']
+			},
+			filterable: true,
       selectable: true,
       clicked: (label, $el, e) => {
         e.preventDefault();

app/assets/stylesheets/pages/boards.scss

@@ -4,13 +4,20 @@
 
 .dropdown-menu-issues-board-new {
   width: 320px;
+
+	.dropdown-content {
+		max-height: 150px;
+	}
 }
 
 .issue-board-dropdown-content {
-  padding: 0px 8px;
+	margin: 0 8px 10px 8px;
+	padding-bottom: 10px;
+	border-bottom: 1px solid $dropdown-divider-color;
 
   > p {
     margin: 0;
+		font-size: 14px;
     color: #9c9c9c;
   }
 }

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

@@ -34,11 +34,7 @@
               %button.btn.btn-create.js-new-board-list{ type: "button", data: { toggle: "dropdown", labels: labels_filter_path } }
                 Create new list
               .dropdown-menu.dropdown-menu-paging.dropdown-menu-align-right.dropdown-menu-issues-board-new
-                = dropdown_title("Create a new list")
-                .issue-board-dropdown-content
-                  %p
-                    Add a list to issue boards by selecting a label below. The list will automatically be populated with issues that have that label. To create a list for a label that doesn't exist yet, simply create the label below.
-                = render partial: "shared/issuable/label_page_default", locals: { show_title: false, show_footer: true, show_create: true }
+                = render partial: "shared/issuable/label_page_default", locals: { show_footer: true, show_create: true, show_boards_content: true, title: "Create a new list" }
                 - if can?(current_user, :admin_label, @project)
                   = render partial: "shared/issuable/label_page_create"
                 = dropdown_loading

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

 - title = local_assigns.fetch(:title, 'Assign labels')
 - show_create = local_assigns.fetch(:show_create, true)
 - show_footer = local_assigns.fetch(:show_footer, true)
-- show_title = local_assigns.fetch(:show_title, true)
 - filter_placeholder = local_assigns.fetch(:filter_placeholder, 'Search labels')
+- show_boards_content = local_assigns.fetch(:show_boards_content, false)
 .dropdown-page-one
-  - if show_title
   = dropdown_title(title)
+  - if show_boards_content
+    .issue-board-dropdown-content
+      %p
+        Add a list to issue boards by selecting a label below. The list will automatically be populated with issues that have that label. To create a list for a label that doesn't exist yet, simply create the label below.
   = dropdown_filter(filter_placeholder)
   = dropdown_content
   - if @project && show_footer