shell32: Do not fail in SHCreateDirectoryExW for ERROR_ALREADY_EXISTS.

dlls/shell32/shlfileop.c

@@ -763,7 +763,9 @@ int WINAPI SHCreateDirectoryExW(HWND hWnd, LPCWSTR path, LPSECURITY_ATTRIBUTES s
 	    }
 	  }
 
-	  if (ret && hWnd && (ERROR_CANCELLED != ret))
+	  if (ret && hWnd &&
+	      ret != ERROR_CANCELLED &&
+	      ret != ERROR_ALREADY_EXISTS)
 	  {
 	    /* We failed and should show a dialog box */
 	    FIXME("Show system error message, creating path %s, failed with error %d\n", debugstr_w(path), ret);

dlls/shell32/tests/shlfileop.c

@@ -2543,6 +2543,7 @@ static void test_unicode(void)
     int ret;
     HANDLE file;
     static const WCHAR UNICODE_PATH_TO[] = {'c',':','\\',0x00ae,0x00ae,'\0'};
+    HWND hwnd;
 
     shfoW.hwnd = NULL;
     shfoW.wFunc = FO_DELETE;
@@ -2633,6 +2634,20 @@ static void test_unicode(void)
     ok(GetLastError() == ERROR_SUCCESS ||
        broken(GetLastError() == ERROR_INVALID_HANDLE), /* WinXp, win2k3 */
        "Expected ERROR_SUCCESS, got %d\n", GetLastError());
+
+    /* Check SHCreateDirectoryExW with a Hwnd
+     * returns ERROR_ALREADY_EXISTS where a directory already exists */
+    /* Get any window handle */
+    hwnd = FindWindowA(NULL, NULL);
+    ok(hwnd != 0, "FindWindowA failed to produce a hwnd\n");
+    ret = SHCreateDirectoryExW(hwnd, UNICODE_PATH, NULL);
+    ok(!ret, "SHCreateDirectoryExW returned %d\n", ret);
+    /* Create already-existing directory */
+    ok(file_existsW(UNICODE_PATH), "The directory was not created\n");
+    ret = SHCreateDirectoryExW(hwnd, UNICODE_PATH, NULL);
+    ok(ret == ERROR_ALREADY_EXISTS,
+       "Expected ERROR_ALREADY_EXISTS, got %d\n", ret);
+    RemoveDirectoryW(UNICODE_PATH);
 }
 
 static void