diff --git a/dom/ipc/BrowserChild.cpp b/dom/ipc/BrowserChild.cpp
index 8948d1da9fe1..bc68ba771941 100644
--- a/dom/ipc/BrowserChild.cpp
+++ b/dom/ipc/BrowserChild.cpp
@@ -1231,6 +1231,27 @@ mozilla::ipc::IPCResult BrowserChild::RecvInitRendering(
   return IPC_OK();
 }
 
+mozilla::ipc::IPCResult BrowserChild::RecvCompositorOptionsChanged(
+    const CompositorOptions& aNewOptions) {
+  MOZ_ASSERT(mCompositorOptions);
+
+  // The only compositor option we currently support changing is APZ
+  // enablement. Even that is only partially supported for now:
+  //   * Going from APZ to non-APZ is fine - we just flip the stored flag.
+  //     Note that we keep the actors (mApzcTreeManager, and the APZChild
+  //     created in InitAPZState()) around (read on for why).
+  //   * Going from non-APZ to APZ is only supported if we were using
+  //     APZ initially (at InitRendering() time) and we are transitioning
+  //     back. In this case, we just reuse the actors which we kept around.
+  //     Fully supporting a non-APZ to APZ transition (i.e. even in cases
+  //     where we initialized as non-APZ) would require setting up the actors
+  //     here. (In that case, we would also have the options of destroying
+  //     the actors in the APZ --> non-APZ case, and always re-creating them
+  //     during a non-APZ --> APZ transition).
+  mCompositorOptions->SetUseAPZ(aNewOptions.UseAPZ());
+  return IPC_OK();
+}
+
 mozilla::ipc::IPCResult BrowserChild::RecvUpdateDimensions(
     const DimensionInfo& aDimensionInfo) {
   // When recording/replaying we need to make sure the dimensions are up to
diff --git a/dom/ipc/BrowserChild.h b/dom/ipc/BrowserChild.h
index c75f124848d0..b684c3c4e27f 100644
--- a/dom/ipc/BrowserChild.h
+++ b/dom/ipc/BrowserChild.h
@@ -278,6 +278,9 @@ class BrowserChild final : public nsMessageManagerScriptExecutor,
       const mozilla::layers::CompositorOptions& aCompositorOptions,
       const bool& aLayersConnected);
 
+  mozilla::ipc::IPCResult RecvCompositorOptionsChanged(
+      const mozilla::layers::CompositorOptions& aNewOptions);
+
   mozilla::ipc::IPCResult RecvUpdateDimensions(
       const mozilla::dom::DimensionInfo& aDimensionInfo);
   mozilla::ipc::IPCResult RecvSizeModeChanged(const nsSizeMode& aSizeMode);
diff --git a/dom/ipc/PBrowser.ipdl b/dom/ipc/PBrowser.ipdl
index 3ddcee84e06b..4f2302671e00 100644
--- a/dom/ipc/PBrowser.ipdl
+++ b/dom/ipc/PBrowser.ipdl
@@ -736,6 +736,8 @@ child:
                         CompositorOptions compositorOptions,
                         bool layersConnected);
 
+    async CompositorOptionsChanged(CompositorOptions newOptions);
+
     async LoadURL(nsCString uri, ShowInfo info);
 
     async ResumeLoad(uint64_t pendingSwitchID, ShowInfo info);
diff --git a/gfx/ipc/CompositorOptions.h b/gfx/ipc/CompositorOptions.h
index 4794ef4fb7bb..31b538b772e2 100644
--- a/gfx/ipc/CompositorOptions.h
+++ b/gfx/ipc/CompositorOptions.h
@@ -46,6 +46,8 @@ class CompositorOptions {
   bool UseAdvancedLayers() const { return mUseAdvancedLayers; }
   bool InitiallyPaused() const { return mInitiallyPaused; }
 
+  void SetUseAPZ(bool aUseAPZ) { mUseAPZ = aUseAPZ; }
+
   void SetUseAdvancedLayers(bool aUseAdvancedLayers) {
     mUseAdvancedLayers = aUseAdvancedLayers;
   }
diff --git a/gfx/layers/ipc/CompositorBridgeChild.cpp b/gfx/layers/ipc/CompositorBridgeChild.cpp
index bf3472911bf1..d4e6ff4a0799 100644
--- a/gfx/layers/ipc/CompositorBridgeChild.cpp
+++ b/gfx/layers/ipc/CompositorBridgeChild.cpp
@@ -839,6 +839,18 @@ mozilla::ipc::IPCResult CompositorBridgeChild::RecvObserveLayersUpdate(
   return IPC_OK();
 }
 
+mozilla::ipc::IPCResult CompositorBridgeChild::RecvCompositorOptionsChanged(
+    const LayersId& aLayersId, const CompositorOptions& aNewOptions) {
+  MOZ_ASSERT(aLayersId.IsValid());
+  MOZ_ASSERT(XRE_IsParentProcess());
+
+  if (RefPtr<dom::BrowserParent> tab =
+          dom::BrowserParent::GetBrowserParentFromLayersId(aLayersId)) {
+    Unused << tab->SendCompositorOptionsChanged(aNewOptions);
+  }
+  return IPC_OK();
+}
+
 void CompositorBridgeChild::HoldUntilCompositableRefReleasedIfNecessary(
     TextureClient* aClient) {
   if (!aClient) {
diff --git a/gfx/layers/ipc/CompositorBridgeChild.h b/gfx/layers/ipc/CompositorBridgeChild.h
index 75f49f505f6a..25973caf831f 100644
--- a/gfx/layers/ipc/CompositorBridgeChild.h
+++ b/gfx/layers/ipc/CompositorBridgeChild.h
@@ -298,6 +298,9 @@ class CompositorBridgeChild final : public PCompositorBridgeChild,
       const LayersId& aLayersId, const LayersObserverEpoch& aEpoch,
       const bool& aActive);
 
+  mozilla::ipc::IPCResult RecvCompositorOptionsChanged(
+      const LayersId& aLayersId, const CompositorOptions& aNewOptions);
+
   uint64_t GetNextResourceId();
 
   void ClearSharedFrameMetricsData(LayersId aLayersId);
diff --git a/gfx/layers/ipc/CompositorBridgeParent.cpp b/gfx/layers/ipc/CompositorBridgeParent.cpp
index e63b7311a51d..22d863db201e 100644
--- a/gfx/layers/ipc/CompositorBridgeParent.cpp
+++ b/gfx/layers/ipc/CompositorBridgeParent.cpp
@@ -1760,6 +1760,7 @@ mozilla::ipc::IPCResult CompositorBridgeParent::RecvAdoptChild(
   RefPtr<APZUpdater> oldApzUpdater;
   APZCTreeManagerParent* parent;
   bool scheduleComposition = false;
+  bool apzEnablementChanged = false;
   RefPtr<ContentCompositorBridgeParent> cpcp;
   RefPtr<WebRenderBridgeParent> childWrBridge;
 
@@ -1794,6 +1795,7 @@ mozilla::ipc::IPCResult CompositorBridgeParent::RecvAdoptChild(
               "Moving tab between windows with different APZ enablement. "
               "This is supported on a best-effort basis, but some things may "
               "break.");
+          apzEnablementChanged = true;
           break;
         }
         case CompositorOptionsChangeKind::eSupported: {
@@ -1864,6 +1866,9 @@ mozilla::ipc::IPCResult CompositorBridgeParent::RecvAdoptChild(
     mApzUpdater->NotifyLayerTreeAdopted(
         WRRootId(child, gfxUtils::GetContentRenderRoot()), oldApzUpdater);
   }
+  if (apzEnablementChanged) {
+    Unused << SendCompositorOptionsChanged(child, mOptions);
+  }
   return IPC_OK();
 }
 
diff --git a/gfx/layers/ipc/PCompositorBridge.ipdl b/gfx/layers/ipc/PCompositorBridge.ipdl
index 137bd824201b..7969c5486bda 100644
--- a/gfx/layers/ipc/PCompositorBridge.ipdl
+++ b/gfx/layers/ipc/PCompositorBridge.ipdl
@@ -155,6 +155,8 @@ child:
 
   async ObserveLayersUpdate(LayersId aLayersId, LayersObserverEpoch aEpoch, bool aActive);
 
+  async CompositorOptionsChanged(LayersId id, CompositorOptions newOptions);
+
 parent:
   async __delete__();