left_sidebar: Improve logic for showing Scheduled messages.

web/src/left_sidebar_navigation_area.js

@@ -15,9 +15,9 @@ export function update_scheduled_messages_row() {
     const $scheduled_li = $(".top_left_scheduled_messages");
     const count = scheduled_messages.get_count();
     if (count > 0) {
-        $scheduled_li.show();
+        $scheduled_li.addClass("show-with-scheduled-messages");
     } else {
-        $scheduled_li.hide();
+        $scheduled_li.removeClass("show-with-scheduled-messages");
     }
     ui_util.update_unread_count_in_dom($scheduled_li, count);
 }

web/src/left_sidebar_navigation_area_popovers.js

@@ -108,8 +108,17 @@ export function initialize() {
     popover_menus.register_popover_menu(".left-sidebar-navigation-menu-icon", {
         ...popover_menus.left_sidebar_tippy_options,
         onShow(instance) {
+            // Determine at show time whether there are scheduled messages,
+            // so that Tippy properly calculates the height of the popover
+            const scheduled_message_count = scheduled_messages.get_count();
+            let has_scheduled_messages = false;
+            if (scheduled_message_count > 0) {
+                has_scheduled_messages = true;
+            }
             popovers.hide_all();
-            instance.setContent(parse_html(render_left_sidebar_condensed_views_popover()));
+            instance.setContent(
+                parse_html(render_left_sidebar_condensed_views_popover({has_scheduled_messages})),
+            );
         },
         onMount() {
             update_unread_count_in_dom(

web/styles/left_sidebar.css

@@ -615,6 +615,15 @@ li.top_left_scheduled_messages {
     }
 }
 
+/* Don't show the scheduled messages item... */
+li.top_left_scheduled_messages {
+    display: none;
+    /* ...unless there are scheduled messages to show. */
+    &.show-with-scheduled-messages {
+        display: list-item;
+    }
+}
+
 .top_left_row {
     padding-left: $far_left_gutter_size;
     padding-right: 10px;

web/templates/popovers/left_sidebar_condensed_views_popover.hbs

@@ -10,6 +10,7 @@
             <span class="unread_count"></span>
         </a>
     </li>
+    {{#if has_scheduled_messages }}
     <li class="condensed-views-popover-menu-scheduled-messages">
         <a tabindex="0" href="#scheduled" class="left-sidebar-popover-icon-label-count">
             <span class="filter-icon">
@@ -19,4 +20,5 @@
             <span class="unread_count"></span>
         </a>
     </li>
+    {{/if}}
 </ul>