The fix in LWListPeer introduced by JDK-7125456 was intended to suppress ItemEvents for programmatic changes to a List, while still allowing events generated by user interaction.

However, the implementation unconditionally bypasses the listener logic:
https://hg.openjdk.org/jdk7u/jdk7u-osx/jdk/rev/dfa991721457
Unfortunately that logic also updates the cached selection state. As a result, when the application select something programmatically, the cached state is not updated.

Consequently, if the user interacts with the List, no ItemEvent may be fired because the peer believes the selection has not changed.