Uncaught TypeError: Cannot read property 'scrollTop' of null

Describe the bug I have an angular app with a component which has encapsulation set to ViewEncapsulation.ShadowDom. Inside the template of this component I’m using a ng-select component. Through items input I’m passing 15 items to ng-select component.

I’m getting an error in the console when:

• I click ng-select component and scroll down in the dropdown
• I click ng-select component, select one of the first top items in the dropdown and then click on it again.

Error that I’m getting is: Uncaught TypeError: Cannot read property 'scrollTop' of null

Through my testing I have noticed that this error appears when:

• a component with encapsulation set to ViewEncapsulation.ShadowDom is using a ng-select component in its template and
• is passing to it an array of items long enough that it creates a scroll bar in a dropdown

I’m setting encapsulation to ViewEncapsulation.ShadowDom because this solves some problems when I’m using the component for @angular/elements.

Reproducible example Example which reproduces described behaviour

To Reproduce Steps to reproduce the behavior:

1. Clone or download the repository provided in reproducible example
2. Build and serve the app using ng serve command
3. Do the steps described above

[snehal4it]

Looks like issue is fixed only in master. We are still using angular8 so is there any plan to apply this fix to 3.x branch (and other branches)?

[bartes]

same issue here when using ViewEncapsulation.ShadowDom

File webpack:///./node_modules/@ng-select/ng-select/fesm2015/ng-select-ng-select.js.pre-build-optimizer.js line 2264 col 53 in l._next (e) => this._onContentScrolled(e.target.scrollTop)));