diff --git a/SMILEBASIC/builtinfunctions.d b/SMILEBASIC/builtinfunctions.d
index fb1ac05..e65d17f 100644
--- a/SMILEBASIC/builtinfunctions.d
+++ b/SMILEBASIC/builtinfunctions.d
@@ -139,7 +139,7 @@ class BuiltinFunction
     }
     static void GCLS(PetitComputer p, DefaultValue!(int, false) color)
     {
-        color.setDefaultValue(p.gcolor);
+        color.setDefaultValue(0);
         p.gfill(p.useGRP, 0, 0, 511, 511, cast(int)color);
     }
     static void GPSET(PetitComputer p, int x, int y, DefaultValue!(int, false) color)
diff --git a/SMILEBASIC/petitcomputer.d b/SMILEBASIC/petitcomputer.d
index 91b49ff..b3bfd24 100644
--- a/SMILEBASIC/petitcomputer.d
+++ b/SMILEBASIC/petitcomputer.d
@@ -152,7 +152,7 @@ class PetitComputer
     bool visibleGRP = true;
     int showGRP;
     int useGRP;
-    uint gcolor;
+    uint gcolor = -1;
     GraphicPage[] GRP;
     GraphicPage GRPF;
     GraphicPage[] GRPFColor;