making clickaway more logical

[chrismcv]

@oliviertassinari - this fixes your animation issue with nested menus

[oliviertassinari]

I may have another approach to solve the issue.
I think that it would be better to add an onRequestClose property
to the Popover component to make it "controllable" as we are doing with the Dialog
or the LeftNav.
This approach would probably save us from using a ref.

[oliviertassinari]

I think that it would be better to add an onRequestClose property

Edit: this property already exist and wasn't working as expected IMHO.
This is an attempt to improve it #2353.