diff --git a/modules/javafx.controls/src/main/java/javafx/scene/control/HeavyweightDialog.java b/modules/javafx.controls/src/main/java/javafx/scene/control/HeavyweightDialog.java
index 5744debd3d5..156ed9ee189 100644
--- a/modules/javafx.controls/src/main/java/javafx/scene/control/HeavyweightDialog.java
+++ b/modules/javafx.controls/src/main/java/javafx/scene/control/HeavyweightDialog.java
@@ -316,7 +316,7 @@ private void updateStageBindings(Window oldOwner, Window newOwner) {
             stage.renderScaleYProperty().unbind();
 
             Scene oldScene = oldStage.getScene();
-            if (scene != null && dialogScene != null) {
+            if (scene != null && dialogScene != null && oldScene != null) {
                 Bindings.unbindContent(dialogScene.getStylesheets(), oldScene.getStylesheets());
             }
         }
@@ -329,7 +329,7 @@ private void updateStageBindings(Window oldOwner, Window newOwner) {
             stage.renderScaleYProperty().bind(newStage.renderScaleYProperty());
 
             Scene newScene = newStage.getScene();
-            if (scene != null && dialogScene != null) {
+            if (scene != null && dialogScene != null && newScene != null) {
                 Bindings.bindContent(dialogScene.getStylesheets(), newScene.getStylesheets());
             }
         }