When applying externalViewport directive, scrollbar ref with @ViewChild decorator gets undefined

[Dozorengel]

Reproduction

Steps to reproduce:

1. Apply externalViewport directive to
2. Use @ViewChild to get reference

Expected Behavior

In ngAfterViewInit hook there is a reference with actual value

Actual Behavior

In ngAfterViewInit hook there is a reference with undefined

Environment

• Angular: 18.0.4
• ngx-scrollbar: 15.0.1
• Browser(s): Edge 126.0
• Operating System (e.g. Windows, macOS, Ubuntu): MacOS Sonoma 14.5