diff --git a/source/code/themes.cpp b/source/code/themes.cpp
index ed28123..89eac92 100644
--- a/source/code/themes.cpp
+++ b/source/code/themes.cpp
@@ -237,7 +237,7 @@ void InitThemes() {
 		}
 	}
 	ReadThemeDataFromFile("custom_themes.json");
-	for (int i=0; i < 4; ++i) {
+	for (int i=1; i <= 4; ++i) {
 		ThemesAddCustomSlot(themes, i);
 	}
 	DumpThemeData();