Index: src/main/java/common/javax/swing/JOptionPane.java =================================================================== --- src/main/java/common/javax/swing/JOptionPane.java (revision 448199) +++ src/main/java/common/javax/swing/JOptionPane.java (working copy) @@ -630,6 +630,9 @@ } private static void setDialogDecorations(final JDialog dialog, final int messageType) { + if (!JDialog.isDefaultLookAndFeelDecorated()) { + return; + } dialog.getRootPane().setWindowDecorationStyle(messageTypeToRootPaneDecoration(messageType)); } } \ No newline at end of file