diff --git a/themes/converse-hd.css b/themes/converse-hd.css
index 571d1c180956387b5367da3e206f30ba939df53f..7bd89ee3d139fb7c8d9d23fc4195432003336e81 100644
--- a/themes/converse-hd.css
+++ b/themes/converse-hd.css
@@ -513,7 +513,7 @@
 
 #conversejs.converse-fullscreen .chatbox .box-flyout {
   bottom: 0;
-  height: 100%;
+  height: 100% !important;
   min-width: auto;
   width: 100%;
 }