diff --git a/macrovision.css b/macrovision.css
index 3e02e610..92383f0a 100644
--- a/macrovision.css
+++ b/macrovision.css
@@ -148,4 +148,9 @@ body {
 .options-row .options-field-unit {
     flex: 1;
     font-size: 150%;
+}
+
+body #test-canvas {
+    position: fixed;
+    top: 100vh;
 }
\ No newline at end of file
diff --git a/macrovision.js b/macrovision.js
index b75f6d44..4801bb33 100644
--- a/macrovision.js
+++ b/macrovision.js
@@ -279,8 +279,10 @@ function clearViewOptions(entity, view) {
 // stack overflow
 // https://stackoverflow.com/questions/38487569/click-through-png-image-only-if-clicked-coordinate-is-transparent
 
-const testCtx = document.createElement("canvas").getContext("2d");
+const testCanvas = document.createElement("canvas");
+testCanvas.id = "test-canvas";
 
+const testCtx = testCanvas.getContext("2d");
 function testClick(event) {
 
     const target = event.target;