Index: src/main/java/common/javax/swing/plaf/basic/BasicPopupMenuUI.java =================================================================== --- src/main/java/common/javax/swing/plaf/basic/BasicPopupMenuUI.java (revision 496250) +++ src/main/java/common/javax/swing/plaf/basic/BasicPopupMenuUI.java (working copy) @@ -95,6 +95,10 @@ } public boolean isPopupTrigger(final MouseEvent event) { + if (event == null) { + throw new NullPointerException(); + } + return false; } }