diff --git a/windows/mdi.c b/windows/mdi.c
new file mode 100644
index 0000000..1912295
--- /dev/null
+++ b/windows/mdi.c
@@ -0,0 +1,448 @@
+/* MDI.C
+ *
+ * Copyright 1994, Bob Amstadt
+ *
+ * This file contains routines to support MDI features.
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include "windows.h"
+#include "win.h"
+#include "mdi.h"
+#include "user.h"
+
+/* #define DEBUG_MDI /* */
+
+/**********************************************************************
+ *					MDIRecreateMenuList
+ */
+void
+MDIRecreateMenuList(MDICLIENTINFO *ci)
+{
+    MDICHILDINFO *chi;
+    char buffer[128];
+    int id, n, index;
+
+#ifdef DEBUG_MDI
+    fprintf(stderr, "MDIRecreateMenuList: hWindowMenu %04.4x\n", 
+	    ci->hWindowMenu);
+#endif
+    
+    id = ci->idFirstChild; 
+    while (DeleteMenu(ci->hWindowMenu, id, MF_BYCOMMAND))
+	id++;
+
+#ifdef DEBUG_MDI
+    fprintf(stderr, "MDIRecreateMenuList: id %04.4x, idFirstChild %04.4x\n", 
+	    id, ci->idFirstChild);
+#endif
+
+    if (!ci->flagMenuAltered)
+    {
+	ci->flagMenuAltered = TRUE;
+	AppendMenu(ci->hWindowMenu, MF_SEPARATOR, 0, NULL);
+    }
+    
+    id = ci->idFirstChild;
+    index = 1;
+    for (chi = ci->infoActiveChildren; chi != NULL; chi = chi->next)
+    {
+	n = sprintf(buffer, "%d ", index++);
+	GetWindowText(chi->hwnd, buffer + n, sizeof(buffer) - n - 1);
+
+#ifdef DEBUG_MDI
+	fprintf(stderr, "MDIRecreateMenuList: id %04.4x, '%s'\n", 
+		id, buffer);
+#endif
+
+	AppendMenu(ci->hWindowMenu, MF_STRING, id++, buffer);
+    }
+}
+
+/**********************************************************************
+ *					MDICreateClient
+ */
+HWND 
+MDICreateClient(WND *w, MDICLIENTINFO *ci, HWND parent, LPMDICREATESTRUCT cs)
+{
+    HWND hwnd;
+
+    /*
+     * Create child window
+     */
+    cs->style &= (WS_MINIMIZE | WS_MAXIMIZE | WS_HSCROLL | WS_VSCROLL);
+    
+    hwnd = CreateWindowEx(0, cs->szClass, cs->szTitle, 
+			  WS_CHILD | WS_BORDER | WS_CAPTION | WS_CLIPSIBLINGS |
+			  WS_MAXIMIZEBOX | WS_MINIMIZEBOX | WS_SYSMENU |
+			  WS_THICKFRAME | WS_VISIBLE | cs->style,
+			  cs->x, cs->y, cs->cx, cs->cy, parent, (HMENU) 0,
+			  w->hInstance, cs->lParam);
+
+    if (hwnd)
+    {
+	HANDLE h = USER_HEAP_ALLOC(GMEM_MOVEABLE, sizeof(MDICHILDINFO));
+	MDICHILDINFO *child_info = USER_HEAP_ADDR(h);
+	if (!h)
+	{
+	    DestroyWindow(hwnd);
+	    return 0;
+	}
+
+	ci->nActiveChildren++;
+	
+	child_info->next = ci->infoActiveChildren;
+	child_info->prev = NULL;
+	child_info->hwnd = hwnd;
+
+	if (ci->infoActiveChildren)
+	    ci->infoActiveChildren->prev = child_info;
+
+	ci->infoActiveChildren = child_info;
+
+	SendMessage(parent, WM_CHILDACTIVATE, 0, 0);
+    }
+	
+    return hwnd;
+}
+
+/**********************************************************************
+ *					MDIDestroyClient
+ */
+HWND 
+MDIDestroyClient(WND *w_parent, MDICLIENTINFO *ci, HWND parent, HWND child,
+		 BOOL flagDestroy)
+{
+    MDICHILDINFO  *chi;
+    
+    chi = ci->infoActiveChildren;
+    while (chi && chi->hwnd != child)
+	chi = chi->next;
+
+    if (chi)
+    {
+	if (chi->prev)
+	    chi->prev->next = chi->next;
+	if (chi->next)
+	    chi->next->prev = chi->prev;
+	if (ci->infoActiveChildren == chi)
+	    ci->infoActiveChildren = chi->next;
+
+	ci->nActiveChildren--;
+	
+	if (chi->hwnd == ci->hwndActiveChild)
+	    SendMessage(parent, WM_CHILDACTIVATE, 0, 0);
+
+	USER_HEAP_FREE((HANDLE) chi);
+	
+	if (flagDestroy)
+	    DestroyWindow(child);
+    }
+    
+    return 0;
+}
+
+/**********************************************************************
+ *					MDIBringChildToTop
+ */
+void MDIBringChildToTop(HWND parent, WORD id, WORD by_id)
+{
+    MDICHILDINFO  *chi;
+    MDICLIENTINFO *ci;
+    WND           *w;
+    int            i;
+
+    w  = WIN_FindWndPtr(parent);
+    ci = (MDICLIENTINFO *) w->wExtra;
+    
+#ifdef DEBUG_MDI
+    fprintf(stderr, "MDIBringToTop: id %04.4x, by_id %d\n", id, by_id);
+#endif
+
+    if (by_id)
+	id -= ci->idFirstChild;
+    if (!by_id || id < ci->nActiveChildren)
+    {
+	chi = ci->infoActiveChildren;
+
+	if (by_id)
+	{
+	    for (i = 0; i < id; i++)
+		chi = chi->next;
+	}
+	else
+	{
+	    while (chi && chi->hwnd != id)
+		chi = chi->next;
+	}
+
+	if (!chi)
+	    return;
+
+#ifdef DEBUG_MDI
+	fprintf(stderr, "MDIBringToTop: child %04.4x\n", chi->hwnd);
+#endif
+	if (chi != ci->infoActiveChildren)
+	{
+	    SetWindowPos(chi->hwnd, HWND_TOP, 0, 0, 0, 0, 
+			 SWP_NOMOVE | SWP_NOSIZE );
+
+	    if (chi->next)
+		chi->next->prev    = chi->prev;
+
+	    if (chi->prev)
+		chi->prev->next    = chi->next;
+	    
+	    chi->prev              = NULL;
+	    chi->next              = ci->infoActiveChildren;
+	    chi->next->prev        = chi;
+	    ci->infoActiveChildren = chi;
+
+	    SendMessage(parent, WM_CHILDACTIVATE, 0, 0);
+	}
+	
+#ifdef DEBUG_MDI
+	fprintf(stderr, "MDIBringToTop: pos %04.4x, hwnd %04.4x\n", 
+		id, chi->hwnd);
+#endif
+    }
+}
+
+/**********************************************************************
+ *					MDIChildActivated
+ */
+LONG MDIChildActivated(WND *w, MDICLIENTINFO *ci, HWND parent)
+{
+    MDICHILDINFO *chi;
+    HWND          deact_hwnd;
+    HWND          act_hwnd;
+    LONG          lParam;
+
+#ifdef DEBUG_MDI
+    fprintf(stderr, "MDIChildActivate: top %04.4x\n", w->hwndChild);
+#endif
+
+    chi = ci->infoActiveChildren;
+    if (chi)
+    {
+	deact_hwnd = ci->hwndActiveChild;
+	act_hwnd   = chi->hwnd;
+	lParam     = ((LONG) deact_hwnd << 16) | act_hwnd;
+
+#ifdef DEBUG_MDI
+	fprintf(stderr, "MDIChildActivate: deact %04.4x, act %04.4x\n",
+	       deact_hwnd, act_hwnd);
+#endif
+
+	ci->hwndActiveChild = act_hwnd;
+
+	if (deact_hwnd != act_hwnd)
+	{
+	    MDIRecreateMenuList(ci);
+	    SendMessage(deact_hwnd,  WM_NCACTIVATE, FALSE, 0);
+	    SendMessage(deact_hwnd, WM_MDIACTIVATE, FALSE, lParam);
+	}
+	
+	SendMessage(act_hwnd,  WM_NCACTIVATE, TRUE, 0);
+	SendMessage(act_hwnd, WM_MDIACTIVATE, TRUE, lParam);
+    }
+
+    if (chi || ci->nActiveChildren == 0)
+    {
+	MDIRecreateMenuList(ci);
+	DrawMenuBar(GetParent(parent));
+    }
+    
+    return 0;
+}
+
+/**********************************************************************
+ *					MDICascade
+ */
+LONG MDICascade(HWND parent, MDICLIENTINFO *ci)
+{
+    MDICHILDINFO *chi;
+    RECT          rect;
+    int           spacing, xsize, ysize;
+    int		  x, y;
+
+    GetClientRect(parent, &rect);
+    spacing = GetSystemMetrics(SM_CYCAPTION) + GetSystemMetrics(SM_CYFRAME);
+    ysize   = abs(rect.bottom - rect.top) - 8 * spacing;
+    xsize   = abs(rect.right  - rect.left) - 8 * spacing;
+    
+#ifdef DEBUG_MDI
+    fprintf(stderr, 
+	    "MDICascade: Client wnd at (%d,%d) - (%d,%d), spacing %d\n", 
+	    rect.left, rect.top, rect.right, rect.bottom, spacing);
+    fprintf(stderr, "MDICascade: searching for last child\n");
+#endif
+    for (chi = ci->infoActiveChildren; chi->next != NULL; chi = chi->next)
+	;
+    
+#ifdef DEBUG_MDI
+    fprintf(stderr, "MDICascade: last child is %04.4x\n", chi->hwnd);
+#endif
+    x = 0;
+    y = 0;
+    for ( ; chi != NULL; chi = chi->prev)
+    {
+#ifdef DEBUG_MDI
+	fprintf(stderr, "MDICascade: move %04.4x to (%d,%d) size [%d,%d]\n", 
+		chi->hwnd, x, y, xsize, ysize);
+#endif
+	SetWindowPos(chi->hwnd, 0, x, y, xsize, ysize, 
+		     SWP_DRAWFRAME | SWP_NOACTIVATE | SWP_NOZORDER);
+
+	x += spacing;
+	y += spacing;
+    }
+
+    return 0;
+}
+
+/**********************************************************************
+ *					MDIClientWndProc
+ *
+ * This function is the handler for all MDI requests.
+ */
+LONG 
+MDIClientWndProc(HWND hwnd, WORD message, WORD wParam, LONG lParam)
+{
+    LPCREATESTRUCT       cs;
+    LPCLIENTCREATESTRUCT ccs;
+    MDICLIENTINFO       *ci;
+    WND                 *w;
+    RECT                 rect;
+
+    w  = WIN_FindWndPtr(hwnd);
+    ci = (MDICLIENTINFO *) w->wExtra;
+    
+    switch (message)
+    {
+      case WM_CHILDACTIVATE:
+	return MDIChildActivated(w, ci, hwnd);
+
+      case WM_CREATE:
+	cs                      = (LPCREATESTRUCT) lParam;
+	ccs                     = (LPCLIENTCREATESTRUCT) cs->lpCreateParams;
+	ci->hWindowMenu         = ccs->hWindowMenu;
+	ci->idFirstChild        = ccs->idFirstChild;
+	ci->infoActiveChildren  = NULL;
+	ci->flagMenuAltered     = FALSE;
+	ci->flagChildMaximized  = FALSE;
+	w->dwStyle             |= WS_CLIPCHILDREN;
+
+	GetClientRect(w->hwndParent, &rect);
+	MoveWindow(hwnd, 0, 0, rect.right, rect.bottom, 1);
+
+	return 0;
+
+      case WM_MDIACTIVATE:
+	MDIBringChildToTop(hwnd, wParam, FALSE);
+	return 0;
+
+      case WM_MDICASCADE:
+	return MDICascade(hwnd, ci);
+
+      case WM_MDICREATE:
+	return MDICreateClient(w, ci, hwnd, (LPMDICREATESTRUCT) lParam);
+
+      case WM_MDIDESTROY:
+	return MDIDestroyClient(w, ci, hwnd, wParam, TRUE);
+
+      case WM_MDIGETACTIVE:
+	return ((LONG) ci->hwndActiveChild | 
+		((LONG) ci->flagChildMaximized << 16));
+
+      case WM_MDIICONARRANGE:
+	/* return MDIIconArrange(...) */
+	break;
+	
+      case WM_MDIMAXIMIZE:
+	ci->flagChildMaximized = TRUE;
+	MDIBringChildToTop(hwnd, wParam, FALSE);
+	return 0;
+
+      case WM_NCACTIVATE:
+	SendMessage(ci->hwndActiveChild, message, wParam, lParam);
+	break;
+	
+      case WM_PARENTNOTIFY:
+	if (wParam == WM_DESTROY)
+	    return MDIDestroyClient(w, ci, hwnd, LOWORD(lParam), FALSE);
+	else if (wParam == WM_LBUTTONDOWN)
+	    MDIBringChildToTop(hwnd, ci->hwndHitTest, FALSE);
+	break;
+
+    }
+    
+    return DefWindowProc(hwnd, message, wParam, lParam);
+}
+
+/**********************************************************************
+ *					DefFrameProc (USER.445)
+ *
+ */
+LONG 
+DefFrameProc(HWND hwnd, HWND hwndMDIClient, WORD message, 
+	     WORD wParam, LONG lParam)
+{
+    switch (message)
+    {
+      case WM_COMMAND:
+	MDIBringChildToTop(hwndMDIClient, wParam, TRUE);
+	break;
+
+      case WM_NCACTIVATE:
+	SendMessage(hwndMDIClient, message, wParam, lParam);
+	break;
+	
+      case WM_SETFOCUS:
+	SendMessage(hwndMDIClient, WM_SETFOCUS, wParam, lParam);
+	break;
+
+      case WM_SIZE:
+	MoveWindow(hwndMDIClient, 0, 0, LOWORD(lParam), HIWORD(lParam), TRUE);
+	break;
+
+    }
+    
+    return DefWindowProc(hwnd, message, wParam, lParam);
+}
+
+/**********************************************************************
+ *					DefMDIChildProc (USER.447)
+ *
+ */
+LONG 
+DefMDIChildProc(HWND hwnd, WORD message, WORD wParam, LONG lParam)
+{
+    MDICLIENTINFO       *ci;
+    WND                 *w;
+
+    w  = WIN_FindWndPtr(GetParent(hwnd));
+    ci = (MDICLIENTINFO *) w->wExtra;
+    
+    switch (message)
+    {
+      case WM_NCHITTEST:
+	ci->hwndHitTest = hwnd;
+	break;
+	
+      case WM_NCPAINT:
+	return NC_DoNCPaint(hwnd, (HRGN)1, 
+			    hwnd == ci->hwndActiveChild);
+    }
+	
+    return DefWindowProc(hwnd, message, wParam, lParam);
+}
+
+/**********************************************************************
+ *					TranslateMDISysAccel (USER.451)
+ *
+ */
+BOOL TranslateMDISysAccel(HWND hwndClient, LPMSG msg)
+{
+    return 0;
+}