diff --git a/repl/src/pianoroll.mjs b/repl/src/pianoroll.mjs
index a7a385ee..094cc98b 100644
--- a/repl/src/pianoroll.mjs
+++ b/repl/src/pianoroll.mjs
@@ -20,6 +20,7 @@ Pattern.prototype.pianoroll = function ({
       events.forEach((event) => {
         const isActive = event.whole.begin <= t && event.whole.end >= t;
         ctx.fillStyle = isActive ? active : inactive;
+        ctx.globalAlpha = event.context.velocity ?? 1;
         const x = Math.round((event.whole.begin / timeframe) * w);
         const width = Math.round(((event.whole.end - event.whole.begin) / timeframe) * w);
         const y = Math.round(h - ((Number(event.value) - minMidi) / midiRange) * h);