--- a/widget/windows/nsWindow.cpp
+++ b/widget/windows/nsWindow.cpp
@@ -5320,21 +5320,18 @@ nsWindow::ProcessMessage(UINT msg, WPARA
         break;
       }
       if (lParam) {
         auto lParamString = reinterpret_cast<const wchar_t*>(lParam);
         if (!wcscmp(lParamString, L"ImmersiveColorSet")) {
           // This might be the Win10 dark mode setting; only way to tell
           // is to actually force a theme change, since we don't get
           // WM_THEMECHANGED or WM_SYSCOLORCHANGE when that happens.
-          if (IsWin10OrLater() && mWindowType == eWindowType_toplevel) {
-            nsIPresShell* presShell = mWidgetListener->GetPresShell();
-            if (presShell) {
-              presShell->ThemeChanged();
-            }
+          if (IsWin10OrLater()) {
+            NotifyThemeChanged();
           }
           // WM_SYSCOLORCHANGE is not dispatched for accent color changes
           OnSysColorChanged();
           break;
         }
         if (IsWin10OrLater() && mWindowType == eWindowType_invisible) {
           if (!wcscmp(lParamString, L"UserInteractionMode")) {
             nsCOMPtr<nsIWindowsUIUtils> uiUtils(do_GetService("@mozilla.org/windows-ui-utils;1"));