diff --git a/view/nsViewManager.cpp b/view/nsViewManager.cpp
index e09ceb4fd264d4..5d87a837b2d4a7 100644
--- a/view/nsViewManager.cpp
+++ b/view/nsViewManager.cpp
@@ -616,53 +616,6 @@ void nsViewManager::DispatchEvent(WidgetGUIEvent* aEvent, nsView* aView,
   *aStatus = nsEventStatus_eIgnore;
 }
 
-// Recursively reparent widgets if necessary
-
-void nsViewManager::ReparentChildWidgets(nsView* aView, nsIWidget* aNewWidget) {
-  MOZ_ASSERT(aNewWidget, "null widget");
-
-  if (nsIWidget* widget = aView->GetWidget()) {
-    // Check to see if the parent widget is the
-    // same as the new parent. If not then reparent
-    // the widget, otherwise there is nothing more
-    // to do for the view and its descendants
-    if (widget->GetParent() != aNewWidget) {
-      widget->SetParent(aNewWidget);
-    }
-    return;
-  }
-
-  // Need to check each of the views children to see
-  // if they have a widget and reparent it.
-
-  for (nsView* kid = aView->GetFirstChild(); kid; kid = kid->GetNextSibling()) {
-    ReparentChildWidgets(kid, aNewWidget);
-  }
-}
-
-// Reparent a view and its descendant views widgets if necessary
-
-void nsViewManager::ReparentWidgets(nsView* aView, nsView* aParent) {
-  MOZ_ASSERT(aParent, "Must have a parent");
-  MOZ_ASSERT(aView, "Must have a view");
-
-  // Quickly determine whether the view has pre-existing children or a
-  // widget. In most cases the view will not have any pre-existing
-  // children when this is called.  Only in the case
-  // where a view has been reparented by removing it from
-  // a reinserting it into a new location in the view hierarchy do we
-  // have to consider reparenting the existing widgets for the view and
-  // it's descendants.
-  if (aView->HasWidget() || aView->GetFirstChild()) {
-    nsIWidget* parentWidget = aParent->GetNearestWidget(nullptr);
-    if (parentWidget) {
-      ReparentChildWidgets(aView, parentWidget);
-      return;
-    }
-    NS_WARNING("Can not find a widget for the parent view");
-  }
-}
-
 void nsViewManager::InsertChild(nsView* aParent, nsView* aChild,
                                 nsView* aSibling, bool aAfter) {
   MOZ_ASSERT(nullptr != aParent, "null ptr");
@@ -682,7 +635,6 @@ void nsViewManager::InsertChild(nsView* aParent, nsView* aChild,
         // insert at end of document order, i.e., before first view
         // this is the common case, by far
         aParent->InsertChild(aChild, nullptr);
-        ReparentWidgets(aChild, aParent);
       } else {
         // insert at beginning of document order, i.e., after last view
         nsView* kid = aParent->GetFirstChild();
@@ -693,7 +645,6 @@ void nsViewManager::InsertChild(nsView* aParent, nsView* aChild,
         }
         // prev is last view or null if there are no children
         aParent->InsertChild(aChild, prev);
-        ReparentWidgets(aChild, aParent);
       }
     } else {
       nsView* kid = aParent->GetFirstChild();
@@ -707,11 +658,9 @@ void nsViewManager::InsertChild(nsView* aParent, nsView* aChild,
       if (aAfter) {
         // insert after 'kid' in document order, i.e. before in view order
         aParent->InsertChild(aChild, prev);
-        ReparentWidgets(aChild, aParent);
       } else {
         // insert before 'kid' in document order, i.e. after in view order
         aParent->InsertChild(aChild, kid);
-        ReparentWidgets(aChild, aParent);
       }
     }
   }
diff --git a/view/nsViewManager.h b/view/nsViewManager.h
index e2e2fc037d5a8d..4655da85d1b8ca 100644
--- a/view/nsViewManager.h
+++ b/view/nsViewManager.h
@@ -309,8 +309,6 @@ class nsViewManager final {
   static void CollectVMsForWillPaint(nsView* aView, nsViewManager* aParentVM,
                                      nsTArray<RefPtr<nsViewManager>>& aVMs);
 
-  void ReparentChildWidgets(nsView* aView, nsIWidget* aNewWidget);
-  void ReparentWidgets(nsView* aView, nsView* aParent);
   void InvalidateWidgetArea(nsView* aWidgetView,
                             const nsRegion& aDamagedRegion);
 
diff --git a/widget/android/nsWindow.cpp b/widget/android/nsWindow.cpp
index 9bfbdf14c98285..c377529e589f98 100644
--- a/widget/android/nsWindow.cpp
+++ b/widget/android/nsWindow.cpp
@@ -2306,7 +2306,7 @@ void nsWindow::OnGeckoViewReady() {
   acc->OnReady();
 }
 
-void nsWindow::DidChangeParent(nsIWidget*) {
+void nsWindow::DidClearParent(nsIWidget*) {
   // if we are now in the toplevel window's hierarchy, schedule a redraw
   if (FindTopLevel() == nsWindow::TopWindow()) {
     RedrawAll();
diff --git a/widget/android/nsWindow.h b/widget/android/nsWindow.h
index 0a8b7c8dba4ee7..64e40b1b5b4f7d 100644
--- a/widget/android/nsWindow.h
+++ b/widget/android/nsWindow.h
@@ -158,7 +158,7 @@ class nsWindow final : public nsBaseWidget {
                                 const LayoutDeviceIntRect& aRect,
                                 InitData* aInitData) override;
   void Destroy() override;
-  void DidChangeParent(nsIWidget* aNewParent) override;
+  void DidClearParent(nsIWidget*) override;
   float GetDPI() override;
   double GetDefaultScaleInternal() override;
   void Show(bool aState) override;
diff --git a/widget/cocoa/nsChildView.h b/widget/cocoa/nsChildView.h
index 528f0170fc0bb1..51d42b9118cbd3 100644
--- a/widget/cocoa/nsChildView.h
+++ b/widget/cocoa/nsChildView.h
@@ -469,7 +469,7 @@ class nsChildView final : public nsBaseWidget {
 
   nsCocoaWindow* GetAppWindowWidget() const;
 
-  void DidChangeParent(nsIWidget*) override;
+  void DidClearParent(nsIWidget*) override;
 
   mozilla::widget::TextInputHandler* GetTextInputHandler() {
     return mTextInputHandler;
diff --git a/widget/cocoa/nsChildView.mm b/widget/cocoa/nsChildView.mm
index 3904661878ba1a..1b975803664531 100644
--- a/widget/cocoa/nsChildView.mm
+++ b/widget/cocoa/nsChildView.mm
@@ -249,7 +249,7 @@ static inline void FlipCocoaScreenCoordinate(NSPoint& inPoint) {
   // mGeckoChild are used throughout the ChildView class to tell if it's safe
   // to use a ChildView object.
   [mView widgetDestroyed];  // Safe if mView is nil.
-  SetParent(nullptr);
+  ClearParent();
   TearDownView();  // Safe if called twice.
 }
 
@@ -524,23 +524,15 @@ static void ManipulateViewWithoutNeedingDisplay(NSView* aView,
 }
 
 // Change the parent of this widget
-void nsChildView::DidChangeParent(nsIWidget*) {
+void nsChildView::DidClearParent(nsIWidget*) {
   NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
 
   if (mOnDestroyCalled) {
     return;
   }
 
-  nsCOMPtr<nsIWidget> kungFuDeathGrip(this);
-
   // we hold a ref to mView, so this is safe
   [mView removeFromSuperview];
-  mParentView = mParent
-                    ? (NSView<mozView>*)mParent->GetNativeData(NS_NATIVE_WIDGET)
-                    : nullptr;
-  if (mParentView) {
-    [mParentView addSubview:mView];
-  }
 
   NS_OBJC_END_TRY_IGNORE_BLOCK;
 }
diff --git a/widget/gtk/nsWindow.cpp b/widget/gtk/nsWindow.cpp
index c023491e780c01..fbe2526b111857 100644
--- a/widget/gtk/nsWindow.cpp
+++ b/widget/gtk/nsWindow.cpp
@@ -715,29 +715,6 @@ bool nsWindow::WidgetTypeSupportsAcceleration() {
   return true;
 }
 
-void nsWindow::DidChangeParent(nsIWidget* aOldParent) {
-  LOG("nsWindow::DidChangeParent new parent %p -> %p\n", aOldParent, mParent);
-  if (!mParent) {
-    return;
-  }
-
-  auto* newParent = static_cast<nsWindow*>(mParent);
-  if (mIsDestroyed || newParent->IsDestroyed()) {
-    return;
-  }
-
-  if (!IsTopLevelWidget()) {
-    GdkWindow* window = GetToplevelGdkWindow();
-    GdkWindow* parentWindow = newParent->GetToplevelGdkWindow();
-    gdk_window_reparent(window, parentWindow, 0, 0);
-    SetHasMappedToplevel(newParent->mHasMappedToplevel);
-    return;
-  }
-
-  GtkWindow* newParentWidget = GTK_WINDOW(newParent->GetGtkWidget());
-  GtkWindowSetTransientFor(GTK_WINDOW(mShell), newParentWidget);
-}
-
 static void InitPenEvent(WidgetMouseEvent& aGeckoEvent, GdkEvent* aEvent) {
   // Find the source of the event
   GdkDevice* device = gdk_event_get_source_device(aEvent);
diff --git a/widget/gtk/nsWindow.h b/widget/gtk/nsWindow.h
index cc16b469242355..a83fee5e9a4f18 100644
--- a/widget/gtk/nsWindow.h
+++ b/widget/gtk/nsWindow.h
@@ -338,7 +338,6 @@ class nsWindow final : public nsBaseWidget {
   void SetTransparencyMode(TransparencyMode aMode) override;
   TransparencyMode GetTransparencyMode() override;
   void SetInputRegion(const InputRegion&) override;
-  void DidChangeParent(nsIWidget* aOldParent) override;
 
   nsresult SynthesizeNativeMouseEvent(LayoutDeviceIntPoint aPoint,
                                       NativeMouseMessage aNativeMessage,
diff --git a/widget/nsBaseWidget.cpp b/widget/nsBaseWidget.cpp
index 62aed4d0ef436c..a7de84625a7773 100644
--- a/widget/nsBaseWidget.cpp
+++ b/widget/nsBaseWidget.cpp
@@ -426,22 +426,20 @@ void nsBaseWidget::BaseCreate(nsIWidget* aParent, widget::InitData* aInitData) {
   }
 }
 
-void nsIWidget::SetParent(nsIWidget* aNewParent) {
+void nsIWidget::ClearParent() {
+  if (!mParent) {
+    return;
+  }
   nsCOMPtr<nsIWidget> kungFuDeathGrip = this;
   nsCOMPtr<nsIWidget> oldParent = mParent;
-  if (mParent) {
-    mParent->RemoveFromChildList(this);
-  }
-  mParent = aNewParent;
-  if (mParent) {
-    mParent->AddToChildList(this);
-  }
-  DidChangeParent(oldParent);
+  oldParent->RemoveFromChildList(this);
+  mParent = nullptr;
+  DidClearParent(oldParent);
 }
 
 void nsIWidget::RemoveAllChildren() {
   while (nsCOMPtr<nsIWidget> kid = mLastChild) {
-    kid->SetParent(nullptr);
+    kid->ClearParent();
     MOZ_ASSERT(kid != mLastChild);
   }
 }
diff --git a/widget/nsIWidget.h b/widget/nsIWidget.h
index 7c929f262a95d8..daebadcb136a39 100644
--- a/widget/nsIWidget.h
+++ b/widget/nsIWidget.h
@@ -513,14 +513,8 @@ class nsIWidget : public nsISupports {
    */
   bool Destroyed() const { return mOnDestroyCalled; }
 
-  /**
-   * Reparent a widget
-   *
-   * Change the widget's parent. Null parents are allowed.
-   *
-   * @param     aNewParent   new parent
-   */
-  void SetParent(nsIWidget* aNewParent);
+  /** Clear the widget's parent. */
+  void ClearParent();
 
   /**
    * Return the parent Widget of this Widget or nullptr if this is a
@@ -531,8 +525,8 @@ class nsIWidget : public nsISupports {
    */
   nsIWidget* GetParent() const { return mParent; }
 
-  /** Gets called when mParent changes after creation. */
-  virtual void DidChangeParent(nsIWidget* aOldParent) {}
+  /** Gets called when mParent is cleared. */
+  virtual void DidClearParent(nsIWidget* aOldParent) {}
 
   /**
    * Return the top level Widget of this Widget
diff --git a/widget/uikit/nsWindow.mm b/widget/uikit/nsWindow.mm
index 6a3ee4fd309c12..9e0055c893e9ef 100644
--- a/widget/uikit/nsWindow.mm
+++ b/widget/uikit/nsWindow.mm
@@ -760,7 +760,7 @@ - (UIAccessibilityContainerType)accessibilityContainerType {
 void nsWindow::Destroy() {
   for (uint32_t i = 0; i < mChildren.Length(); ++i) {
     // why do we still have children?
-    mChildren[i]->SetParent(nullptr);
+    mChildren[i]->ClearParent();
   }
 
   if (mParent) mParent->mChildren.RemoveElement(this);
diff --git a/widget/windows/nsWindow.cpp b/widget/windows/nsWindow.cpp
index 2458409879e6ac..2f6d842c532568 100644
--- a/widget/windows/nsWindow.cpp
+++ b/widget/windows/nsWindow.cpp
@@ -1441,13 +1441,11 @@ void nsWindow::DissociateFromNativeWindow() {
   mPrevWndProc.reset();
 }
 
-void nsWindow::DidChangeParent(nsIWidget*) {
+void nsWindow::DidClearParent(nsIWidget*) {
   if (mWindowType == WindowType::Popup || !mWnd) {
     return;
   }
-  HWND newParent =
-      mParent ? (HWND)mParent->GetNativeData(NS_NATIVE_WINDOW) : nullptr;
-  ::SetParent(mWnd, newParent);
+  ::SetParent(mWnd, nullptr);
   RecreateDirectManipulationIfNeeded();
 }
 
diff --git a/widget/windows/nsWindow.h b/widget/windows/nsWindow.h
index 4231b535de4eaf..88ea1cc685e96a 100644
--- a/widget/windows/nsWindow.h
+++ b/widget/windows/nsWindow.h
@@ -195,7 +195,7 @@ class nsWindow final : public nsBaseWidget {
   void Destroy() override;
   float GetDPI() override;
   double GetDefaultScaleInternal() override;
-  void DidChangeParent(nsIWidget* aOldParent) override;
+  void DidClearParent(nsIWidget* aOldParent) override;
   int32_t LogToPhys(double aValue);
   mozilla::DesktopToLayoutDeviceScale GetDesktopToDeviceScale() override {
     if (mozilla::widget::WinUtils::IsPerMonitorDPIAware()) {