Disable double back by default

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

@@ -690,7 +690,7 @@ public class ActivityView extends ActivityBilling implements FragmentManager.OnB
                 super.onBackPressed();
             else if (!backHandled()) {
                 SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(ActivityView.this);
-                boolean double_back = prefs.getBoolean("double_back", true);
+                boolean double_back = prefs.getBoolean("double_back", false);
                 if (searching || !double_back)
                     super.onBackPressed();
                 else {

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

@@ -461,6 +461,9 @@ public class ApplicationEx extends Application
         } else if (version < 1535) {
             editor.remove("identities_asked");
             editor.remove("identities_primary_hint");
+        } else if (version < 1539) {
+            if (!prefs.contains("double_back"))
+                editor.putBoolean("double_back", true);
         }
 
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O && !BuildConfig.DEBUG)

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

@@ -436,7 +436,7 @@ public class FragmentOptionsBehavior extends FragmentBase implements SharedPrefe
         SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getContext());
 
         swSyncOnlaunch.setChecked(prefs.getBoolean("sync_on_launch", false));
-        swDoubleBack.setChecked(prefs.getBoolean("double_back", true));
+        swDoubleBack.setChecked(prefs.getBoolean("double_back", false));
         swConversationActions.setChecked(prefs.getBoolean("conversation_actions", true));
         swConversationActionsReplies.setChecked(prefs.getBoolean("conversation_actions_replies", true));
         swConversationActionsReplies.setEnabled(swConversationActions.isChecked());