IME does not work in EditableTextBox in WidgetComponent

void FSlateEditableTextLayout::FTextInputMethodContext::CacheWindow()
{
	if (!OwnerLayout)
	{
		return;
	}

	const TSharedRef<const SWidget> OwningSlateWidgetPtr = OwnerLayout->OwnerWidget->GetSlateWidget();
#if 0
	CachedParentWindow = FSlateApplication::Get().FindWidgetWindow(OwningSlateWidgetPtr);
#else  //workaround
	TSharedPtr<SWindow> SlateWindow = FSlateApplication::Get().FindWidgetWindow(OwningSlateWidgetPtr);
	if (SlateWindow->IsVirtualWindow())
	{
		SlateWindow = FSlateApplication::Get().GetActiveTopLevelRegularWindow();
	}
	CachedParentWindow = SlateWindow;
#endif
}