patch 7.4.1369
Problem:    Channels don't have a queue for stderr.
Solution:   Have a queue for each part of the channel.
diff --git a/src/gui_w32.c b/src/gui_w32.c
index 5129c5f..f3da794 100644
--- a/src/gui_w32.c
+++ b/src/gui_w32.c
@@ -1930,15 +1930,15 @@
 #ifdef FEAT_CHANNEL
     if (msg.message == WM_NETBEANS)
     {
-	int	    what;
-	channel_T   *channel = channel_fd2channel((sock_T)msg.wParam, &what);
+	int	    part;
+	channel_T   *channel = channel_fd2channel((sock_T)msg.wParam, &part);
 
 	if (channel != NULL)
 	{
 	    /* Disable error messages, they can mess up the display and throw
 	     * an exception. */
 	    ++emsg_off;
-	    channel_read(channel, what, "process_message");
+	    channel_read(channel, part, "process_message");
 	    --emsg_off;
 	}
 	return;