Added hint

app/src/main/java/eu/faircode/email/FragmentOAuth.java

@@ -125,6 +125,7 @@ public class FragmentOAuth extends FragmentBase {
     private ContentLoadingProgressBar pbOAuth;
     private TextView tvConfiguring;
     private TextView tvGmailHint;
+    private TextView tvGmailLoginHint;
 
     private TextView tvError;
     private TextView tvOfficeAuthHint;
@@ -177,6 +178,7 @@ public class FragmentOAuth extends FragmentBase {
         pbOAuth = view.findViewById(R.id.pbOAuth);
         tvConfiguring = view.findViewById(R.id.tvConfiguring);
         tvGmailHint = view.findViewById(R.id.tvGmailHint);
+        tvGmailLoginHint = view.findViewById(R.id.tvGmailLoginHint);
 
         tvError = view.findViewById(R.id.tvError);
         tvOfficeAuthHint = view.findViewById(R.id.tvOfficeAuthHint);
@@ -267,6 +269,7 @@ public class FragmentOAuth extends FragmentBase {
         pbOAuth.setVisibility(View.GONE);
         tvConfiguring.setVisibility(View.GONE);
         tvGmailHint.setVisibility("gmail".equals(id) ? View.VISIBLE : View.GONE);
+        tvGmailLoginHint.setVisibility("gmail".equals(id) ? View.VISIBLE : View.GONE);
         hideError();
 
         etName.setText(personal);
@@ -429,6 +432,7 @@ public class FragmentOAuth extends FragmentBase {
                 redirectUri = Uri.parse("eu.faircode.email.debug:/");
             }
 
+            // https://openid.net/specs/openid-connect-core-1_0.html#AuthRequest
             AuthorizationRequest.Builder authRequestBuilder =
                     new AuthorizationRequest.Builder(
                             serviceConfig,

app/src/main/res/layout/fragment_oauth.xml

@@ -175,6 +175,17 @@
             app:layout_constraintStart_toStartOf="parent"
             app:layout_constraintTop_toBottomOf="@id/tvConfiguring" />
 
+        <TextView
+            android:id="@+id/tvGmailLoginHint"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="12dp"
+            android:text="@string/title_setup_gmail_login"
+            android:textAppearance="@style/TextAppearance.AppCompat.Small"
+            android:textStyle="italic|bold"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@id/tvGmailHint" />
+
         <TextView
             android:id="@+id/tvErrorTitle"
             android:layout_width="wrap_content"
@@ -184,7 +195,7 @@
             android:textAppearance="@style/TextAppearance.AppCompat.Medium"
             android:textStyle="bold"
             app:layout_constraintStart_toStartOf="parent"
-            app:layout_constraintTop_toBottomOf="@id/tvGmailHint" />
+            app:layout_constraintTop_toBottomOf="@id/tvGmailLoginHint" />
 
         <TextView
             android:id="@+id/tvError"

app/src/main/res/values/strings.xml

@@ -221,6 +221,7 @@
     <string name="title_setup_gmail_support">Authorizing Google accounts will work in the Play Store and GitHub version only because Android checks the digital app signature</string>
     <string name="title_setup_gmail_rationale">Please grant permissions to select an account and read your name</string>
     <string name="title_setup_gmail_permissions">Google will ask for permissions to read, compose, send and permanently delete all your email. FairEmail will never delete your messages without your explicit consent.</string>
+    <string name="title_setup_gmail_login">If Chrome is signed in to an account, a new account can only be added through Android. This can be avoided by logging out of Chrome via the Chrome sync settings.</string>
     <string name="title_setup_gmail_on_device">Why do I need to select an on-device account?</string>
     <string name="title_setup_gmail_password">I want to authorize an account with a password instead of an on-device account</string>
     <string name="title_setup_office_auth">The error \'AUTHENTICATE failed\' can be caused by IMAP/SMTP being disabled by the system administrator</string>