How to set focus to UserControl (make it selectable)?

Question

I need to set focus to UserControl itself, not its child.
Otherwise I cannot implement insertion from the buffer. :(
Setting Focusable=True

Answer 1

The whole problem was in my misunderstanding of controls' behavior.
This SO question clearly shows it I believe.

Thus, setting UserControl.Focusable = true is not sufficient. To make it navigatable via keyboard IsTabStop must be true also. And to make UC selectable by mouse click we should call Focus() in mouse eventhandler. That's it.