Unable to input with IME in widget component.

Unable to input IME text in widget component, but able to input IME text in textbox like UMG designer.  It works fine until 4.21, however it wasn't able to work after 4.22.

Workaround:

void FSlateEditableTextLayout::FTextInputMethodContext::CacheWindow()
{
    if (!OwnerLayout)
    {
        return;
    }
    const TSharedRef<const SWidget> OwningSlateWidgetPtr = OwnerLayout->OwnerWidget->GetSlateWidget();

#if 0
    CachedParentWindow = FSlateApplication::Get().FindWidgetWindow(OwningSlateWidgetPtr);
#else
    FWidgetPath WidgetPath;
    CachedParentWindow = FSlateApplication::Get().FindWidgetWindow(OwningSlateWidgetPtr, WidgetPath);
#endif
}

[Steps]

1. Create new widget and add MultiLineEditableText.

2. Create new blueprint actor and add widget component.

3. Set the following value in widget component. 

      Widget Class = User Widget Class making step1

      Drawing at Desired Size = true

      Receive Hardware Input = true

4.Placed blueprint actor in level viewport.

5. Run PIE.

6. Moving mouse cursor and click on widget component.

7. Input text with enabling IME in widget component (e.g. adding Japanese text).

Expect:

 can input text with IME.

Result:

 unable to input text with IME.