diff --git a/ace/index.html b/ace/index.html
index f3680e5..cf53ea1 100644
--- a/ace/index.html
+++ b/ace/index.html
@@ -84,10 +84,8 @@
             function updateToolbar() {
                 document.getElementById("btnUndo").disabled = !editor.session.getUndoManager().hasUndo();
                 document.getElementById("btnRedo").disabled = !editor.session.getUndoManager().hasRedo();
-                if (window.fullscreen) {
-                  document.getElementById("btnFs").style.display = "none";
-                } else {
-                  document.getElementById("btnFs").style.display = "block";
+                if (!window.fullscreen) {
+                    document.getElementById("btnFs").style.display = "block";
                 }
             }
             editor.on("input", updateToolbar);
@@ -126,6 +124,7 @@
                     } else if (elem.msRequestFullscreen) { /* IE/Edge */
                         elem.msRequestFullscreen();
                     }
+                    document.getElementById("btnFs").style.display = "none";
                 }
                 else {
                     if (document.exitFullscreen) {