Fix controlbox position in fullscreen mode

sass/_controlbox.scss

@@ -61,6 +61,7 @@
     }
 
     #controlbox {
+        order: -1;
 
         .open-rooms-toggle, .open-rooms-toggle .fa {
             color: var(--chatroom-head-color) !important;
@@ -377,7 +378,6 @@
     }
 
     #controlbox {
-        order: -1;
         min-width: var(--controlbox-width) !important;
         width: var(--controlbox-width);
         .box-flyout {
@@ -436,6 +436,13 @@
     }
 }
 
+#conversejs.converse-embedded,
+#conversejs.converse-fullscreen{
+    .toggle-controlbox {
+        display: none;
+    }
+}
+
 #conversejs.converse-embedded,
 #conversejs.converse-fullscreen,
 #conversejs.converse-mobile {