Index: src/main/java/common/javax/swing/plaf/basic/BasicComboBoxUI.java =================================================================== --- src/main/java/common/javax/swing/plaf/basic/BasicComboBoxUI.java (revision 490626) +++ src/main/java/common/javax/swing/plaf/basic/BasicComboBoxUI.java (working copy) @@ -420,6 +420,9 @@ public void paintCurrentValueBackground(final Graphics g, final Rectangle bounds, final boolean hasFocus) { Color oldColor = g.getColor(); + if (comboBox == null) { + throw new NullPointerException("comboBox is null"); + } if (hasFocus) { g.setColor(UIManager.getColor("ComboBox.selectionBackground")); } else {