Fix xscreen

SMILEBASIC/petitcomputer.d

@@ -477,11 +477,14 @@ class PetitComputer
                 this.bg[i].display = 0;
                 this.bg[i].clip;
             }
+            if (currentDisplay.rect.length > 1)
+            {
                 for(int i = bgmax; i < this.bg.length; i++)
                 {
                     this.bg[i].display = 1;
                     this.bg[i].clip;
                 }
+            }
             for (int i = cast(int)currentDisplay.rect.length - 1; i >= 0; i--)
             {
                 display(i);