🚀 go-pugleaf

I'm having a problem utilizing a shared IDCMP port setup on a window
arrangement, and wonder if anyone can see a problem with what I'm doing.
I have one main window, and a second window is opened, after which I make
the following assignment;
 
secondwin->UserPort = firstwindow->UserPort;
 
Ok...all's well, all of my messages are coming into the first window's
UserPort.  I don't need to check the IDCMPWindow portion of my IntuiMessages,
due to the arrangement I have set up, but rather just ReplyMsg() to each
message I process as if it were from one window.  Now, the problem comes when
I try to close the second window.  NOw, I realize you cannot simply do this
normally, so I use the following routine:
 
void SafeClose(swin)
struct Window *swin;
{
    struct IntuiMessage *msg;
    struct IntuiMessage *succ;
    struct MsgPort      *mp = (struct MsgPort *)swin->UserPort;
 
    Forbid();
    msg = (struct IntuiMessage *)mp->mp_MsgList.lh_Head;
    while(succ=(struct IntuiMessage *)msg->ExecMessage.mn_Node.ln_Succ) {
        if (msg->IDCMPWindow == swin) {
           Remove(msg);
           ReplyMsg(msg);
        }
        msg = succ;
    }
    swin->UserPort = NULL;
    Permit();
    CloseWindow(swin);
}

Generally, calling this results in a corrupt memory list guru. Now, anyone
have a suggestion?  I realize this is an old topic, but I cannot find
referernces to it presently.  


                             LaMonte Koop
 Internet: lkoop@pnet01.cts.com         ARPA: crash!pnet01!lkoop@nosc.mil
           UUCP: {hplabs!hp-sdd ucsd nosc}!crash!pnet01!lkoop
  A scientist is one who finds interest in the kinetic energy of Jell-O
   moving at ridiculous velocities...an engineer is one who can find a
               real-life application for such silliness.