Dropdown closes when some focused element inside remove/redraw

[slavik990]

Here the plunker - http://plnkr.co/edit/n9kJ8cerRpX4yBFDinXQ?p=preview
Seems problem in

ng2-semantic-ui/src/modules/dropdown/directives/dropdown.ts

Line 121 in 1cebf2a

if (!this._element.nativeElement.contains(e.relatedTarget)) {

- when focus element removed, execute focusout event with : e.relatedTarget === null

[edcarroll]

Have added to the next milestone, thank you for the easy repro 🎉