From 792db26ff1591f9e054486f1bee01c422e774101 Mon Sep 17 00:00:00 2001
From: Sofien-Sellami <73444179+Sofien-Sellami@users.noreply.github.com>
Date: Mon, 6 Oct 2025 13:56:31 +0100
Subject: [PATCH] fix: Safely handle missing active viewport (#5448)

---
 .../StudyPrefetcherService/StudyPrefetcherService.ts         | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/platform/core/src/services/StudyPrefetcherService/StudyPrefetcherService.ts b/platform/core/src/services/StudyPrefetcherService/StudyPrefetcherService.ts
index 398974eb3..a6862f485 100644
--- a/platform/core/src/services/StudyPrefetcherService/StudyPrefetcherService.ts
+++ b/platform/core/src/services/StudyPrefetcherService/StudyPrefetcherService.ts
@@ -291,6 +291,11 @@ class StudyPrefetcherService extends PubSubService {
     }
 
     const activeViewport = viewports.get(activeViewportId);
+
+    if (!activeViewport) {
+      return;
+    }
+
     const displaySetUpdated = this._setActiveDisplaySetsUIDs(activeViewport.displaySetInstanceUIDs);
 
     if (forceRestart || displaySetUpdated) {