By means of 6776743 all lightweight components are considered opaque by the HW/LW mixing code. If a component needs to be transparent, it must be specifically marked so using the newly introduced com.sun.awt.AWTUtilities.setComponentNonOpaqueForMixing() method.

If an existing application embedds a heavyweight component in a frame, and at the same time installs a custom glass pane, the heavyweight component will disappear. This regression is not very serious since we never supported mixing of hw and lw components in general. The developer will have two options to resolve the problem:

1. By modifying the software to tag the glass pane properly, or

2. To suggest users to use the sun.awt.disableMixing system property to disable the hw/lw mixing code at all.