code: public String removeId(IDbgpSession session)
  	{
  		final PerSessionInfo info;
  		synchronized (sessions)
  		{
  			info = (PerSessionInfo) sessions.remove(session);
  		}
  		return info != null ? info.identifier : null;
  	}
docs: /*
  @see IScriptBreakpoint#removeId(IDbgpSession)