This allows developers to set child children component must be the
currently active/focused one.
This can be used to "control" where the focus is, without user
interactions.
This fix the bug from:
https://github.com/ArthurSonzogni/FTXUI/pull/11
About:
~~~
Bug: Focus handling not working
in the examples (e.g. checkbox.cpp) I can toggle the individual
checkboxes but I cannot move between items, I tried to understand the
focus implementation but am I unsure which keypresses would move focus
between different components
~~~