UI fix for excessively long topic name

css/base.css

@@ -459,6 +459,8 @@ div.alert .content {
 }
 
 #topic-view {
+  position: relative;
+  overflow-x: hidden;
   display: flex;
   flex-direction: column;
   width: 100%;
@@ -606,6 +608,7 @@ table.permission-editor td.checkbox {
   height: 4rem;
   white-space: nowrap;
   box-shadow: 0 1px 2px gray;
+  overflow-x: hidden;
   z-index: 1; /* otherwise the shadow becomes invisible */
 }
 
@@ -1066,10 +1069,6 @@ i.search {
 /* END of sidepanel styles */
 
 /* Topic/messages view */
-#topic-view {
-  position: relative;
-}
-
 #topic-caption-panel {
   background-color: #b0bec5;
 }
@@ -1096,6 +1095,10 @@ i.search {
   line-height: 3rem;
 }
 
+#topic-title-group {
+  overflow-x: hidden;
+}
+
 #hide-message-view {
   display: block;
   margin-right: 0.35rem;