WM_NEXTDLGCTL should not change the default button ID (based on a
patch by Krishna Murthy).

dlls/user/tests/dialog.c

diff --git a/dlls/user/tests/dialog.c b/dlls/user/tests/dialog.c
index 19967a9..52dcd8e 100644
--- a/dlls/user/tests/dialog.c
+++ b/dlls/user/tests/dialog.c
@@ -588,7 +588,7 @@
          * Check whether the default button ID got changed by sending message "WM_NEXTDLGCTL"
          */
         dwVal = DefDlgProcA(g_hwndTestDlg, DM_GETDEFID, 0, 0);
-        todo_wine ok ( IDCANCEL == (LOWORD(dwVal)), "WM_NEXTDLGCTL changed default button\n");
+        ok ( IDCANCEL == (LOWORD(dwVal)), "WM_NEXTDLGCTL changed default button\n");
 
         /*
          * Check whether the style of the button which got the focus, changed to BS_DEFPUSHBUTTON and
@@ -621,7 +621,7 @@
          */
         if ( IDCANCEL == (LOWORD(dwVal)) )
         {
-            todo_wine ok ( ((GetWindowLong( g_hwndTestDlgBut2, GWL_STYLE)) & BS_DEFPUSHBUTTON),
+                ok ( ((GetWindowLong( g_hwndTestDlgBut2, GWL_STYLE)) & BS_DEFPUSHBUTTON),
                         "Button2 style not set to BS_DEFPUSHBUTTON\n" );
 
                 ok ( !((GetWindowLong( g_hwndTestDlgBut1, GWL_STYLE)) & BS_DEFPUSHBUTTON),
@@ -638,7 +638,7 @@
          * Check whether the default button ID got changed by sending message "WM_NEXTDLGCTL"
          */
         dwVal = DefDlgProcA(g_hwndTestDlg, DM_GETDEFID, 0, 0);
-        todo_wine ok ( IDCANCEL == (LOWORD(dwVal)), "WM_NEXTDLGCTL changed default button\n");
+        ok ( IDCANCEL == (LOWORD(dwVal)), "WM_NEXTDLGCTL changed default button\n");
     }
 }
 

windows/defdlg.c

diff --git a/windows/defdlg.c b/windows/defdlg.c
index 0d9f1f0..def5b8a 100644
--- a/windows/defdlg.c
+++ b/windows/defdlg.c
@@ -127,14 +127,15 @@
 
 
 /***********************************************************************
- *           DEFDLG_SetDefButton
+ *           DEFDLG_SetDefId
  *
- * Set the new default button to be hwndNew.
+ * Set the default button id.
  */
-static BOOL DEFDLG_SetDefButton( HWND hwndDlg, DIALOGINFO *dlgInfo, WPARAM wParam )
+static BOOL DEFDLG_SetDefId( HWND hwndDlg, DIALOGINFO *dlgInfo, WPARAM wParam)
 {
     DWORD dlgcode=0; /* initialize just to avoid a warning */
-    HWND hwndNew = GetDlgItem(hwndDlg, wParam);
+    HWND hwndOld, hwndNew = GetDlgItem(hwndDlg, wParam);
+    INT old_id = dlgInfo->idResult;
 
     dlgInfo->idResult = wParam;
     if (hwndNew &&
@@ -142,15 +143,54 @@
             & (DLGC_UNDEFPUSHBUTTON | DLGC_BUTTON)))
         return FALSE;  /* Destination is not a push button */
 
-    if (dlgInfo->idResult)  /* There's already a default pushbutton */
-    {
-        HWND hwndOld = GetDlgItem( hwndDlg, dlgInfo->idResult );
-        if (hwndOld && (SendMessageA( hwndOld, WM_GETDLGCODE, 0, 0) & DLGC_DEFPUSHBUTTON))
-            SendMessageA( hwndOld, BM_SETSTYLE, BS_PUSHBUTTON, TRUE );
-    }
+    /* Make sure the old default control is a valid push button ID */
+    hwndOld = GetDlgItem( hwndDlg, old_id );
+    if (!hwndOld || !(SendMessageA( hwndOld, WM_GETDLGCODE, 0, 0) & DLGC_DEFPUSHBUTTON))
+        hwndOld = DEFDLG_FindDefButton( hwndDlg );
+    if (hwndOld && hwndOld != hwndNew)
+        SendMessageA( hwndOld, BM_SETSTYLE, BS_PUSHBUTTON, TRUE );
+
     if (hwndNew)
     {
-        if(dlgcode==DLGC_UNDEFPUSHBUTTON)
+        if(dlgcode & DLGC_UNDEFPUSHBUTTON)
+            SendMessageA( hwndNew, BM_SETSTYLE, BS_DEFPUSHBUTTON, TRUE );
+    }
+    return TRUE;
+}
+
+
+/***********************************************************************
+ *           DEFDLG_SetDefButton
+ *
+ * Set the new default button to be hwndNew.
+ */
+static BOOL DEFDLG_SetDefButton( HWND hwndDlg, DIALOGINFO *dlgInfo, HWND hwndNew )
+{
+    DWORD dlgcode=0; /* initialize just to avoid a warning */
+    HWND hwndOld = GetDlgItem( hwndDlg, dlgInfo->idResult );
+
+    if (hwndNew &&
+        !((dlgcode=SendMessageW(hwndNew, WM_GETDLGCODE, 0, 0 ))
+            & (DLGC_UNDEFPUSHBUTTON | DLGC_DEFPUSHBUTTON)))
+    {
+        /**
+         * Need to draw only default push button rectangle.
+         * Since the next control is not a push button, need to draw the push
+         * button rectangle for the default control.
+         */
+        hwndNew = hwndOld;
+        dlgcode = SendMessageW(hwndNew, WM_GETDLGCODE, 0, 0 );
+    }
+
+    /* Make sure the old default control is a valid push button ID */
+    if (!hwndOld || !(SendMessageA( hwndOld, WM_GETDLGCODE, 0, 0) & DLGC_DEFPUSHBUTTON))
+        hwndOld = DEFDLG_FindDefButton( hwndDlg );
+    if (hwndOld && hwndOld != hwndNew)
+        SendMessageA( hwndOld, BM_SETSTYLE, BS_PUSHBUTTON, TRUE );
+
+    if (hwndNew)
+    {
+        if(dlgcode & DLGC_UNDEFPUSHBUTTON)
             SendMessageA( hwndNew, BM_SETSTYLE, BS_DEFPUSHBUTTON, TRUE );
     }
     return TRUE;
@@ -214,7 +254,7 @@
 
         case DM_SETDEFID:
             if (dlgInfo && !(dlgInfo->flags & DF_END))
-                DEFDLG_SetDefButton( hwnd, dlgInfo, wParam );
+                DEFDLG_SetDefId( hwnd, dlgInfo, wParam );
             return 1;
 
         case DM_GETDEFID:
@@ -235,7 +275,7 @@
                 if (!lParam)
                     hwndDest = GetNextDlgTabItem(hwnd, GetFocus(), wParam);
                 if (hwndDest) DEFDLG_SetFocus( hwnd, hwndDest );
-                DEFDLG_SetDefButton( hwnd, dlgInfo, GetDlgCtrlID(hwndDest) );
+                DEFDLG_SetDefButton( hwnd, dlgInfo, hwndDest );
             }
             return 0;