using KeyModifier with KeyEvent

Hello,

I'm building a 3D annotation tool using Open3D gui.

I'm using keyEvent class to implement key callbacks (set_on_key of SceneWidget class). I want to use KeyModifier class with KeyEvent, but there is no function called (is_modifier_down) as in MouseEvent class. I think it would be convenient to add a similar function to KeyEvent class to be able to implement key bindings to change the functionality of a keystroke. So, this functionality is either missing or I couldn't find the correct way to do it in the documentation/examples.

Also another small suggestion, please add some photos of the gui example apps to the documentation/github or add something in the description. The gui class is great interface but without pictures, one is not sure what is possible to implement with it and can easily miss that it exist or that there are examples of it somewhere.