IE only: Focus gets lost after selecting value per keyboard

[platzhersh]

Describe the bug
In IE, when you select a value from the dropdown by pressing "ENTER" the field loses focus. If I press tab after, focus goes to the very first clickable element of the website again, isntead of continueing with the field right after the ngx select ex element.

To Reproduce
see above. stackblitz didnt work

Expected behavior
Focus should not be lost, but kept, so a user can navigate through the whole site.