diff --git a/ts/routes/image-occlusion/mask-editor.ts b/ts/routes/image-occlusion/mask-editor.ts
index c5492d413..b632abf98 100644
--- a/ts/routes/image-occlusion/mask-editor.ts
+++ b/ts/routes/image-occlusion/mask-editor.ts
@@ -106,6 +106,9 @@ function initCanvas(): fabric.Canvas {
     fabric.Object.prototype.cornerStyle = "circle";
     fabric.Object.prototype.cornerStrokeColor = "#000000";
     fabric.Object.prototype.padding = 8;
+    // snap rotation around 0 by +-3deg
+    fabric.Object.prototype.snapAngle = 360;
+    fabric.Object.prototype.snapThreshold = 3;
     // disable rotation when selecting
     canvas.on("selection:created", () => {
         const g = canvas.getActiveObject();