diff --git a/guacamole-common-js/src/main/resources/layer.js b/guacamole-common-js/src/main/resources/layer.js
index 64ccd0329..eb0ba7e95 100644
--- a/guacamole-common-js/src/main/resources/layer.js
+++ b/guacamole-common-js/src/main/resources/layer.js
@@ -405,7 +405,7 @@ Guacamole.Layer = function(width, height) {
         scheduleTask(function() {
             if (layer.autosize != 0) fitRect(x, y, w, h);
             displayContext.fillStyle = "rgba("
-                        + r + "," + g + "," + b + "," + a + ")";
+                        + r + "," + g + "," + b + "," + a / 255 + ")";
             displayContext.fillRect(x, y, w, h);
         });
     };