src/share/classes/javax/swing/Popup.java

*** 225,240 ****
       */
      static class HeavyWeightWindow extends JWindow implements ModalExclude {
          HeavyWeightWindow(Window parent) {
              super(parent);
              setFocusableWindowState(false);
!             Toolkit tk = Toolkit.getDefaultToolkit();
!             if (tk instanceof SunToolkit) {
!                 // all the short-lived windows like Popups should be
!                 // OverrideRedirect on X11 platforms
!                 ((SunToolkit)tk).setOverrideRedirect(this);
!             }
              // Popups are typically transient and most likely won't benefit
              // from true double buffering.  Turn it off here.
              getRootPane().setUseTrueDoubleBuffering(false);
              // Try to set "always-on-top" for the popup window.
              // Applets usually don't have sufficient permissions to do it.
--- 225,236 ----
       */
      static class HeavyWeightWindow extends JWindow implements ModalExclude {
          HeavyWeightWindow(Window parent) {
              super(parent);
              setFocusableWindowState(false);
!             setType(Window.Type.POPUP);
! 
              // Popups are typically transient and most likely won't benefit
              // from true double buffering.  Turn it off here.
              getRootPane().setUseTrueDoubleBuffering(false);
              // Try to set "always-on-top" for the popup window.
              // Applets usually don't have sufficient permissions to do it.