Ngb Pop Over

<ng-template #popoverContent>
    <myComp>
    </myComp>
</ng-template>

<button
    type="button"
    class="btn"
    [disabled]="flag"
    placement="left"
    [ngbPopover]="popoverContent"
    popoverTitle="test"
    data-container="body"
    (click)="onClick($event)"
>

ngbPopover is the @Input ngbPopover in ngbPopover directive
ngbPopover directive tag is by attribute etc <a attribute>
when directive is loaded, can also lazy assign other Input such as popOverTitle, data-container,

Override css:

:host ::ng-deep .popover {

    / }
https://github.com/valor-software/ngx-bootstrap/issues/1707

https://stackoverflow.com/questions/17297701/bootstrap-popover-isnt-placed-correctly-even-with-container-body-set