Fixed incorrect on close value

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

@@ -1144,6 +1144,10 @@ public class ApplicationEx extends Application
             editor.remove("setup_reminder");
         editor.putInt("last_sdk", Build.VERSION.SDK_INT);
 
+        String onclose = prefs.getString("onclose", null);
+        if ("none".equals(onclose))
+            editor.remove("onclose");
+
         editor.apply();
     }
 

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

@@ -480,7 +480,7 @@ public class FragmentOptionsBehavior extends FragmentBase implements SharedPrefe
             public void onItemSelected(AdapterView<?> adapterView, View view, int position, long id) {
                 String[] values = getResources().getStringArray(R.array.onCloseValues);
                 String value = values[position];
-                if (TextUtils.isEmpty(value))
+                if ("none".equals(value))
                     prefs.edit().remove("onclose").apply();
                 else
                     prefs.edit().putString("onclose", value).apply();