Results 3 issues of Stephen James

Need to resolve circular references, by "privatising" link back to parent and only exposing that via a "getter" method. Deeper issue here is private values using Base.

Using Trigger with `contextMenu` supports closing on window blur, in order to cover when a user clicks/taps on an iframe, but when we use `click` as a trigger, this was...

**Behaviour:** When using rc-trigger (eg. via Ant Design's `Dropdown`) with a `click` type of trigger, the popup will not be closed if a user clicks or taps on an iframe...