> I tried to change implementation this API which takes variable length argument.

Thanks!!!

> I think that it almost good. But, I do not fully understand what you mean "Gdk::Event::CURRENT_TIME will be suitable for the default value of time".

It means that the following codes are the same meaning:

```ruby
device.ungrab                                               # No argument. Use Gdk::Event::CURRENT_TIME is used as the default value
device.ungrab(Gdk::Event::CURRENT_TIME) # Specifies Gdk::Event::CURRENT_TIME explicity
```