angular / angular/components

bug(cdk-virtual-scroll-viewport): Does not work with ngZoneRunCoalescing

Open
#25,808 3 comments 0 reactions 0 assignees View on GitHub
area: cdk/scrolling P3
Dominant language
TypeScript
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Description

### Is this a regression?

- [ ] Yes, this behavior used to work in the previous version

### The previous version in which this bug was not present was

_No response_

### Description

cdk-virtual-scroll-viewport does not work with ngZoneRunCoalescing enabled. Some frames are rendered with incorrect content, causing visual "glitches".

### Reproduction

Steps to reproduce:
1. Go to https://stackblitz.com/edit/cdk-virtual-scroll-bug-run-coalescing
2. Scroll . The bug is most apparent when scrolling slowly.

### Expected Behavior

All rendered frames has correct content during scrolling.

### Actual Behavior

Some frames are rendered with incorrect content, causing glitches.

### Environment

- Angular: 14.2.6
- CDK/Material: 14.2.5
- Browser(s): Safari, Chrome
- Operating System (e.g. Windows, macOS, Ubuntu): iOS, macOS

Contributor guide

Open the contributing guide

Research direction

Start with the linked StackBlitz reproduction and the cdk-virtual-scroll-viewport behavior while ngZoneRunCoalescing is enabled; compare slow scrolling in Chrome or Safari on the listed Angular 14 environment. Done means every rendered frame shows the correct content during scrolling without visual glitches.

Written by the indexing model from the issue text.

Assessment

Tech stack
angular, typescript
Domain
frontend
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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