minor fixes

build.gradle

@@ -134,7 +134,8 @@ run {
                                  "--add-opens=javafx.graphics/com.sun.javafx.menu=centerdevice.nsmenufx",
                                  "--add-opens=javafx.graphics/com.sun.glass.ui=com.sparrowwallet.sparrow",
                                  "--add-opens=javafx.graphics/com.sun.javafx.application=com.sparrowwallet.sparrow",
-                                 "--add-opens=java.base/java.net=com.sparrowwallet.sparrow"]
+                                 "--add-opens=java.base/java.net=com.sparrowwallet.sparrow",
+                                 "--add-opens=java.base/java.io=com.google.gson"]
 
     if(os.macOsX) {
         applicationDefaultJvmArgs += ["-Xdock:name=Sparrow", "-Xdock:icon=/Users/scy/git/sparrow/src/main/resources/sparrow-large.png",
@@ -179,6 +180,7 @@ jlink {
                    "--add-opens=javafx.graphics/com.sun.glass.ui=com.sparrowwallet.sparrow",
                    "--add-opens=javafx.graphics/com.sun.javafx.application=com.sparrowwallet.sparrow",
                    "--add-opens=java.base/java.net=com.sparrowwallet.sparrow",
+                   "--add-opens=java.base/java.io=com.google.gson",
                    "--add-reads=com.sparrowwallet.merged.module=java.desktop",
                    "--add-reads=com.sparrowwallet.merged.module=java.sql",
                    "--add-reads=com.sparrowwallet.merged.module=com.sparrowwallet.sparrow",

src/main/java/com/sparrowwallet/sparrow/whirlpool/WhirlpoolController.java

@@ -248,6 +248,7 @@ public class WhirlpoolController {
             nbOutputsLoading.setText("Calculating...");
             nbOutputs.setVisible(false);
             discountFeeBox.setVisible(false);
+            tx0PreviewProperty.set(null);
         });
         tx0PreviewService.setOnSucceeded(workerStateEvent -> {
             Tx0Preview tx0Preview = tx0PreviewService.getValue();