Timing issue when processing data from an XML stream

Running a preview on an XML datasource causes a freezing of the gui. The main thread is stuck trying SocketInputStream.socketRead0, which never returns.

The jboss log indicates a BlockedException has occurred and only when designer is forcibly terminated does the input stream read get cancelled.

Discussions over the log indicate ...
'... a timing issue where the asynch processing thread notifies after the processing thread has been detached and there's no other action that restarts the plan'

Server log snippet attached.