Merge remote-tracking branch 'origin/develop' into threecolumn

* origin/develop:
  Fix tab switcher not working when some tabs hidden
  Fix mobile nav link text colour
  Fix shrug text in muted status

src/components/mobile_nav/mobile_nav.vue

@@ -94,6 +94,9 @@
     grid-template-columns: 2fr auto;
     width: 100%;
     box-sizing: border-box;
+    a {
+      color: var(--topBarLink, $fallback--link);
+    }
   }
 
   .mobile-inner-nav {

src/components/tab_switcher/tab_switcher.jsx

@@ -50,7 +50,7 @@ export default {
     activeIndex () {
       // In case of controlled component
       if (this.activeTab) {
-        return this.slots().findIndex(slot => this.activeTab === slot.props.key)
+        return this.slots().findIndex(slot => slot && slot.props && this.activeTab === slot.props.key)
       } else {
         return this.active
       }

src/components/thread_tree/thread_tree.vue

 <template>
-  <div class="thread-tree panel-body">
+  <div class="thread-tree">
     <status
       :key="status.id"
       ref="statusComponent"