minor fixes

src/main/java/com/sparrowwallet/sparrow/wallet/UtxosController.java

@@ -123,7 +123,7 @@ public class UtxosController extends WalletFormController implements Initializab
         AppServices.onlineProperty().addListener(new WeakChangeListener<>(mixingOnlineListener));
 
         utxosTable.getSelectionModel().getSelectedIndices().addListener((ListChangeListener<Integer>) c -> {
-            List<Entry> selectedEntries = utxosTable.getSelectionModel().getSelectedCells().stream().map(tp -> tp.getTreeItem().getValue()).collect(Collectors.toList());
+            List<Entry> selectedEntries = utxosTable.getSelectionModel().getSelectedCells().stream().filter(tp -> tp.getTreeItem() != null).map(tp -> tp.getTreeItem().getValue()).collect(Collectors.toList());
             utxosChart.select(selectedEntries);
             updateButtons(Config.get().getBitcoinUnit());
         });

src/main/java/com/sparrowwallet/sparrow/whirlpool/dataSource/SparrowIndexHandler.java

@@ -63,8 +63,8 @@ public class SparrowIndexHandler extends AbstractIndexHandler {
             } else if(walletNode.getKeyPurpose() == KeyPurpose.CHANGE) {
                 wallet.getMixConfig().setChangeIndex(index);
             }
-        }
 
-        EventManager.get().post(new WalletMixConfigChangedEvent(wallet));
+            EventManager.get().post(new WalletMixConfigChangedEvent(wallet));
+        }
     }
 }