diff --git a/app/assets/javascripts/app/views/channel/chat.jst.eco b/app/assets/javascripts/app/views/channel/chat.jst.eco
index fe78a1aa4..fe7c88246 100644
--- a/app/assets/javascripts/app/views/channel/chat.jst.eco
+++ b/app/assets/javascripts/app/views/channel/chat.jst.eco
@@ -42,7 +42,7 @@
       </div>
       <style>@import "/assets/chat/chat.css";</style>
       <div class="chat-demo-animationHolder">
-        <div class="js-chat zammad-chat zammad-chat-is-loaded zammad-chat-is-shown is-open">
+        <div class="js-chat zammad-chat zammad-chat-is-open zammad-chat-is-loaded zammad-chat-is-shown is-open">
           <div class="zammad-chat-header js-toggle-chat js-backgroundColor js-chatHeader">
             <div class="zammad-chat-header-controls">
               <span class="zammad-chat-agent-status" data-status="online"><%- @T('Online') %></span>
diff --git a/app/assets/stylesheets/zammad.scss b/app/assets/stylesheets/zammad.scss
index 7cbd31da6..9d6217087 100644
--- a/app/assets/stylesheets/zammad.scss
+++ b/app/assets/stylesheets/zammad.scss
@@ -7827,6 +7827,25 @@ output {
     transition: 500ms;
     user-select: none;
     will-change: transform;
+
+    &.is-fullscreen {
+      right: 0;
+      width: 100%;
+      height: 100%;
+      border-radius: 0 !important;
+      
+      .zammad-chat-header {
+        border-radius: 0 !important;
+        box-shadow:
+          0 -1px rgba(0,0,0,.1),
+          0 -1px rgba(0,0,0,.1) inset,
+          0 1px 1px rgba(0,0,0,.13);
+      }
+
+      .zammad-chat-controls {
+        border-radius: 0 0 5px 5px;
+      }
+    }
     
     &.no-transition {
       transition: none;
diff --git a/public/assets/chat/chat.css b/public/assets/chat/chat.css
index b07c7dda5..fea95e2c9 100644
--- a/public/assets/chat/chat.css
+++ b/public/assets/chat/chat.css
@@ -58,9 +58,6 @@
     .zammad-chat-header {
       border-radius: 0 !important; } }
 
-.zammad-chat.is-fullscreen .zammad-chat-header {
-  border-radius: 0 !important; }
-
 .zammad-chat.zammad-chat-is-open .zammad-chat-header {
   cursor: default; }
 
diff --git a/public/assets/chat/chat.scss b/public/assets/chat/chat.scss
index 9bf6d3731..1791f5c13 100644
--- a/public/assets/chat/chat.scss
+++ b/public/assets/chat/chat.scss
@@ -35,6 +35,7 @@
   }
 }
 
+
 .zammad-chat-icon {
   height: 2em;
   width: 2em;
@@ -64,10 +65,6 @@
   }
 }
 
-.zammad-chat.is-fullscreen .zammad-chat-header {
-  border-radius: 0 !important;
-}
-
 .zammad-chat.zammad-chat-is-open .zammad-chat-header {
   cursor: default;
 }