modules/javafx.controls/src/main/java/javafx/scene/control/skin/ComboBoxBaseSkin.java

*** 164,174 ****
              final double w, final double h) {
          if (displayNode == null) {
              updateDisplayArea();
          }
  
!         final double arrowWidth = snapSize(arrow.prefWidth(-1));
          final double arrowButtonWidth = (isButton()) ? 0 :
                  arrowButton.snappedLeftInset() + arrowWidth +
                  arrowButton.snappedRightInset();
  
          if (displayNode != null) {
--- 164,174 ----
              final double w, final double h) {
          if (displayNode == null) {
              updateDisplayArea();
          }
  
!         final double arrowWidth = snapSizeX(arrow.prefWidth(-1));
          final double arrowButtonWidth = (isButton()) ? 0 :
                  arrowButton.snappedLeftInset() + arrowWidth +
                  arrowButton.snappedRightInset();
  
          if (displayNode != null) {
*** 187,197 ****
      @Override protected double computePrefWidth(double height, double topInset, double rightInset, double bottomInset, double leftInset) {
          if (displayNode == null) {
              updateDisplayArea();
          }
  
!         final double arrowWidth = snapSize(arrow.prefWidth(-1));
          final double arrowButtonWidth = isButton() ? 0 :
                                          arrowButton.snappedLeftInset() +
                                          arrowWidth +
                                          arrowButton.snappedRightInset();
          final double displayNodeWidth = displayNode == null ? 0 : displayNode.prefWidth(height);
--- 187,197 ----
      @Override protected double computePrefWidth(double height, double topInset, double rightInset, double bottomInset, double leftInset) {
          if (displayNode == null) {
              updateDisplayArea();
          }
  
!         final double arrowWidth = snapSizeX(arrow.prefWidth(-1));
          final double arrowButtonWidth = isButton() ? 0 :
                                          arrowButton.snappedLeftInset() +
                                          arrowWidth +
                                          arrowButton.snappedRightInset();
          final double displayNodeWidth = displayNode == null ? 0 : displayNode.prefWidth(height);