diff --git a/win32ss/include/ntuser.h b/win32ss/include/ntuser.h
index b997b21c848..22538c84818 100644
--- a/win32ss/include/ntuser.h
+++ b/win32ss/include/ntuser.h
@@ -726,6 +726,8 @@ typedef struct _WND
     PSBINFOEX pSBInfoex; // convert to PSBINFO
     /* Entry in the list of thread windows. */
     LIST_ENTRY ThreadListEntry;
+
+    PVOID DialogPointer;
 } WND, *PWND;
 
 #define PWND_BOTTOM ((PWND)1)
diff --git a/win32ss/user/ntuser/simplecall.c b/win32ss/user/ntuser/simplecall.c
index 462bbe15bb7..fdc52c1c478 100644
--- a/win32ss/user/ntuser/simplecall.c
+++ b/win32ss/user/ntuser/simplecall.c
@@ -798,9 +798,10 @@ NtUserCallHwndParam(
             UserRefObjectCo(pWnd, &Ref);
 
             if (pWnd->head.pti->ppi == PsGetCurrentProcessWin32Process() &&
-                pWnd->cbwndExtra == DLGWINDOWEXTRA &&
+                pWnd->cbwndExtra >= DLGWINDOWEXTRA &&
                 !(pWnd->state & WNDS_SERVERSIDEWINDOWPROC))
             {
+                pWnd->DialogPointer = (PVOID)Param;
                 if (Param)
                 {
                     if (!pWnd->fnid) pWnd->fnid = FNID_DIALOG;
diff --git a/win32ss/user/user32/controls/button.c b/win32ss/user/user32/controls/button.c
index 6b65c536795..69377a96b2d 100644
--- a/win32ss/user/user32/controls/button.c
+++ b/win32ss/user/user32/controls/button.c
@@ -72,7 +72,7 @@ WINE_DEFAULT_DEBUG_CHANNEL(button);
 #define BUTTON_HFONT_GWL_OFFSET  (sizeof(LONG))
 #define HIMAGE_GWL_OFFSET (BUTTON_HFONT_GWL_OFFSET+sizeof(HFONT))
 #define BUTTON_UISTATE_GWL_OFFSET (HIMAGE_GWL_OFFSET+sizeof(HFONT))
-#define NB_EXTRA_BYTES    (BUTTON_UISTATE_GWL_OFFSET+sizeof(LONG))
+#define NB_EXTRA_BYTES    (BUTTON_UISTATE_GWL_OFFSET+sizeof(LONG_PTR))
 
 /* undocumented flags */
 #define BUTTON_NSTATES         0x0F
diff --git a/win32ss/user/user32/windows/dialog.c b/win32ss/user/user32/windows/dialog.c
index c853e5f8ebd..359cfd150c6 100644
--- a/win32ss/user/user32/windows/dialog.c
+++ b/win32ss/user/user32/windows/dialog.c
@@ -36,9 +36,7 @@ WINE_DEFAULT_DEBUG_CHANNEL(user32);
 
 #define DF_END  0x0001
 #define DF_DIALOGACTIVE 0x4000 // ReactOS
-#define DWLP_ROS_DIALOGINFO (DWLP_USER+sizeof(ULONG_PTR))
 #define GETDLGINFO(hwnd) DIALOG_get_info(hwnd, FALSE)
-#define SETDLGINFO(hwnd, info) SetWindowLongPtrW((hwnd), DWLP_ROS_DIALOGINFO, (LONG_PTR)(info))
 #define GET_WORD(ptr)  (*(WORD *)(ptr))
 #define GET_DWORD(ptr) (*(DWORD *)(ptr))
 #define GET_LONG(ptr) (*(const LONG *)(ptr))
@@ -141,7 +139,7 @@ DIALOGINFO *DIALOG_get_info( HWND hWnd, BOOL create )
        return NULL;
     }
 
-    dlgInfo = (DIALOGINFO *)GetWindowLongPtrW( hWnd, DWLP_ROS_DIALOGINFO );
+    dlgInfo = pWindow->DialogPointer;
 
     if (!dlgInfo && create)
     {
@@ -151,7 +149,7 @@ DIALOGINFO *DIALOG_get_info( HWND hWnd, BOOL create )
                 return NULL;
 
             dlgInfo->idResult = IDOK;
-            SETDLGINFO( hWnd, dlgInfo );
+            NtUserxSetDialogPointer( hWnd, dlgInfo );
        }
        else
        {
@@ -159,13 +157,6 @@ DIALOGINFO *DIALOG_get_info( HWND hWnd, BOOL create )
        }
     }
 
-    if (dlgInfo)
-    {
-        if (!(pWindow->state & WNDS_DIALOGWINDOW))
-        {
-           NtUserxSetDialogPointer( hWnd, dlgInfo );
-        }
-    }
     return dlgInfo;
 }
 
@@ -1258,7 +1249,8 @@ static LRESULT DEFDLG_Proc( HWND hwnd, UINT msg, WPARAM wParam,
         }
         case WM_NCDESTROY:
 //// ReactOS
-            if ((dlgInfo = (DIALOGINFO *)SetWindowLongPtrW( hwnd, DWLP_ROS_DIALOGINFO, 0 )))
+            dlgInfo = DIALOG_get_info(hwnd, FALSE);
+            if (dlgInfo != NULL)
             {
                 if (dlgInfo->hUserFont) DeleteObject( dlgInfo->hUserFont );
                 if (dlgInfo->hMenu) DestroyMenu( dlgInfo->hMenu );