--- a/widget/gtk/GtkCompositorWidget.cpp
+++ b/widget/gtk/GtkCompositorWidget.cpp
@@ -64,16 +64,18 @@ GtkCompositorWidget::GtkCompositorWidget
         (void*)mWidget.get(), (void*)mWidget, !!mIsRenderingSuspended);
   }
 #endif
 }
 
 GtkCompositorWidget::~GtkCompositorWidget() {
   LOG("GtkCompositorWidget::~GtkCompositorWidget [%p]\n", (void*)mWidget.get());
   DisableRendering();
+  RefPtr<nsIWidget> widget = mWidget.forget();
+  NS_ReleaseOnMainThread("GtkCompositorWidget::mWidget", widget.forget());
 }
 
 already_AddRefed<gfx::DrawTarget> GtkCompositorWidget::StartRemoteDrawing() {
   return nullptr;
 }
 void GtkCompositorWidget::EndRemoteDrawing() {}
 
 already_AddRefed<gfx::DrawTarget>

--- a/widget/gtk/nsWindow.cpp
+++ b/widget/gtk/nsWindow.cpp
@@ -568,25 +568,19 @@ void nsWindow::DestroyChildWindows() {
     nsWindow* kid = get_window_for_gdk_window(child);
     if (kid) {
       kid->Destroy();
     }
   }
 }
 
 void nsWindow::Destroy() {
-  // Allow to call ~nsWindow from different thread (Compositor for instance)
-  // in case that nsWindow is already destroyed.
-  if (mIsDestroyed) {
-    return;
-  }
-
   MOZ_DIAGNOSTIC_ASSERT(NS_IsMainThread());
 
-  if (!mCreated) {
+  if (mIsDestroyed || !mCreated) {
     return;
   }
 
   LOG("nsWindow::Destroy\n");
 
   mIsDestroyed = true;
   mCreated = false;
 

--- a/widget/gtk/nsWindow.h
+++ b/widget/gtk/nsWindow.h
@@ -621,17 +621,17 @@ class nsWindow final : public nsBaseWidg
   // threads.
   //
   // FIXME(emilio): GetTitlebarRect() reads other things that TSAN doesn't
   // catch because mDrawInTitlebar is false on automation ~always. We should
   // probably make GetTitlebarRect() simpler / properly thread-safe.
   mozilla::Atomic<bool, mozilla::Relaxed> mDrawInTitlebar{false};
 
   // Has this widget been destroyed yet?
-  mozilla::Atomic<bool> mIsDestroyed;
+  bool mIsDestroyed;
   // mIsShown tracks requested visible status from browser perspective, i.e.
   // if the window should be visible or now.
   bool mIsShown : 1;
   // mNeedsShow is set when browser requested to show this window but we failed
   // to do so for some reason (wrong window size for instance).
   // In such case we set mIsShown = true and mNeedsShow = true to indicate
   // that the window is not actually visible but we report to browser that
   // it is visible (mIsShown == true).