Error message for setfullScreen

vite/src/pipedal/AppThemed.tsx

@@ -259,12 +259,16 @@ function setFullScreen(value: boolean) {
     if (docEl.requestFullscreen) // the latest offical api.
     {
         if (value) {
-            window.document.documentElement.requestFullscreen({ navigationUI: "hide" });
-        } else {
-            window.document.exitFullscreen();
-        }
+            window.document.documentElement.requestFullscreen({ navigationUI: "hide" })
+                .then(() => { })
+                .catch((err) => {
+                    alert(
+                        `Unable to switch into fullscreen mode: ${err.message} (${err.name})`,
+                    );
+                });
             return;
         }
+    }
 
     var requestFullScreen = docEl.requestFullscreen || docEl.mozRequestFullScreen || docEl.webkitRequestFullscreen || docEl.msRequestFullScreen;
     var cancelFullScreen = docEl.exitFullscreen || doc.mozCancelFullScreen || doc.webkitExitFullscreen || doc.msExitFullscreen;
@@ -1161,7 +1165,7 @@ export
 
         );
     }
-    };
+};
 
 
 const AppThemed = withStyles(AppThemedBase, appStyles);