diff --git a/dll/win32/comdlg32/filedlg.c b/dll/win32/comdlg32/filedlg.c
index cf1d2bc34c2..54bbc544aab 100644
--- a/dll/win32/comdlg32/filedlg.c
+++ b/dll/win32/comdlg32/filedlg.c
@@ -3099,6 +3099,7 @@ BOOL FILEDLG95_OnOpen(HWND hwnd)
         /* Attach the file extension with file name*/
         ext = PathFindExtensionW(lpstrPathAndFile);
 #ifdef __REACTOS__
+        if (*ext == UNICODE_NULL && fodInfos->defext)
         {
             LPWSTR filterExt = NULL, lpstrFilter = NULL, pch, pchNext;
             LPCWSTR the_ext = NULL;