diff --git a/ReadMe.txt b/ReadMe.txt
index 066e2db..b8076e0 100644
--- a/ReadMe.txt
+++ b/ReadMe.txt
@@ -62,7 +62,7 @@ Version 2.3 (2021-02-xx)
 	TODO: Inform if the connection is not possible.
 	TODO: What's happen if I hot unplug?
 	TODO: Check the self test about UART (http://regis.cosnier.free.fr/private/private.php?journal=HP48&index=-4637&nomenu)
-- Allows pressing a calculator button with the right button of the mouse but prevents its release to allow the On+A+F key combination (with Android version >= 5.0).
+- Allows pressing a calculator button with the right button of the mouse and prevents its release to allow the On+A+F key combination (with Android version >= 5.0).
 - Update the embedded help file "Emu48.html" to the latest version.
 - Open an external web browser when you click an external links in the Help.
 
diff --git a/app/build.gradle b/app/build.gradle
index 000cf43..bf48f81 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -80,6 +80,7 @@ android {
         sourceCompatibility = '1.8'
         targetCompatibility = '1.8'
     }
+    ndkVersion '22.1.7171670'
 }
 
 dependencies {
diff --git a/app/src/main/cpp/win32-layer.c b/app/src/main/cpp/win32-layer.c
index 192b34b..d130f48 100644
--- a/app/src/main/cpp/win32-layer.c
+++ b/app/src/main/cpp/win32-layer.c
@@ -31,8 +31,8 @@ extern JavaVM *java_machine;
 extern jobject bitmapMainScreen;
 extern AndroidBitmapInfo androidBitmapInfo;
 
-HANDLE hWnd;
-LPTSTR szTitle;
+extern HANDLE hWnd;
+extern LPTSTR szTitle;
 LPTSTR szCurrentAssetDirectory = NULL;
 LPTSTR szCurrentContentDirectory = NULL;
 AAssetManager * assetManager;