diff --git a/src/filetypes.c b/src/filetypes.c
index 11a428ea6..e625c5377 100644
--- a/src/filetypes.c
+++ b/src/filetypes.c
@@ -654,15 +654,14 @@ filetype *filetypes_detect_from_file(gint idx)
 filetype *filetypes_detect_from_filename(const gchar *utf8_filename)
 {
 	GPatternSpec *pattern;
+	gchar *base_filename;
 	gint i, j;
 
 	// to match against the basename of the file(because of Makefile*)
+	base_filename = g_path_get_basename(utf8_filename);
 #ifdef G_OS_WIN32
-	gchar *tmp = g_path_get_basename(utf8_filename);
-	gchar *base_filename = g_utf8_strdown(tmp, -1);
-	g_free(tmp);
-#else
-	gchar *base_filename = g_path_get_basename(utf8_filename);
+	// use lower case basename
+	setptr(base_filename, g_utf8_strdown(base_filename, -1));
 #endif
 
 	for(i = 0; i < GEANY_MAX_FILE_TYPES; i++)