diff --git a/platform/ui.jcef/jcef/SettingsHelper.java b/platform/ui.jcef/jcef/SettingsHelper.java
index 9569a3f886f8..a2673cd50612 100644
--- a/platform/ui.jcef/jcef/SettingsHelper.java
+++ b/platform/ui.jcef/jcef/SettingsHelper.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2024 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+// Copyright 2000-2026 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
 package com.intellij.ui.jcef;
 
 import com.intellij.execution.Platform;
@@ -187,6 +187,14 @@ final class SettingsHelper {
         doTrackGPUCrashes.set(true);
     }
 
+    if (settings.windowless_rendering_enabled && RegistryManager.getInstance().is("ide.browser.jcef.osr.siteIsolation.disable")) {
+      // In OSR mode wheel events routed to an unscrollable cross-origin iframe are not bubbled back to the parent page,
+      // so page scrolling gets stuck while the pointer is over such an iframe, e.g. a YouTube embed on the What's New page.
+      // Disabling site isolation keeps cross-origin iframes in the parent's renderer where Blink handles scroll chaining itself.
+      // See https://github.com/chromiumembedded/cef/issues/3325
+      args = ArrayUtil.mergeArrays(args, "--disable-site-isolation-trials");
+    }
+
     // Sometimes it's useful to be able to pass any additional keys (see IDEA-248140)
     // NOTE: List of keys: https://peter.sh/experiments/chromium-command-line-switches/
     String extraArgsProp = System.getProperty("ide.browser.jcef.extra.args", "");
diff --git a/platform/util/resources/misc/registry.properties b/platform/util/resources/misc/registry.properties
index 297ddc9fa98c..9a5be1160d09 100644
--- a/platform/util/resources/misc/registry.properties
+++ b/platform/util/resources/misc/registry.properties
@@ -422,6 +422,9 @@ ide.browser.jcef.osr.enabled.restartRequired=true
 ide.browser.jcef.osr.enabled.description=Enable per-browser off-screen rendering mode for JCEF
 ide.browser.jcef.osr.wheelRotation.factor=40
 ide.browser.jcef.osr.wheelRotation.factor.description=The factor to multiply MouseWheelEvent.getWheelRotation() in a buffered OSR browser.
+ide.browser.jcef.osr.siteIsolation.disable=true
+ide.browser.jcef.osr.siteIsolation.disable.restartRequired=true
+ide.browser.jcef.osr.siteIsolation.disable.description=Disables Chromium site isolation (site-per-process) when JCEF off-screen rendering is enabled. Works around page scrolling getting stuck while the mouse pointer is over a cross-origin iframe (e.g., a YouTube video on the What's New page). Set to false to keep site isolation enabled.
 ide.browser.jcef.osr.measureFPS.id=OSR JCEF FPS Meter
 ide.browser.jcef.osr.measureFPS.id.description=JCEF OSR browser FPS Meter string ID.
 ide.browser.jcef.osr.measureFPS.scroll=false