diff --git a/src/blocks.js b/src/blocks.js
index 69b6e57e..9f4b188e 100644
--- a/src/blocks.js
+++ b/src/blocks.js
@@ -9313,7 +9313,7 @@ InputSlotMorph.prototype.fixLayout = function () {
     contents.isEditable = (!this.isReadOnly);
     if (this.isReadOnly) {
         contents.disableSelecting();
-        contents.color = new Color(254, 254, 254);
+        contents.color = new Color(255, 255, 255);
     } else {
         contents.enableSelecting();
         contents.color = new Color(0, 0, 0);