height of app should always fill screen (not more or less)

src/ui/web/css/layout.css

@@ -50,6 +50,11 @@ body {
     min-height: 0;
     display: flex;
     flex-direction: column;
+    height: 100%;
+}
+
+.TimelinePanel ul {
+    flex: 1 0 0;
 }
 
 .RoomHeader {

src/ui/web/css/timeline.css

@@ -1,6 +1,5 @@
 
 .TimelinePanel ul {
-    flex: 1;
     overflow-y: auto;
     list-style: none;
     padding: 0;