angular / angular/components

bug(FlexibleConnectedPositionStrategy): Incorrect position on mobile browsers when address bar is hidden

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#27,739 0 comments 7 reactions 0 assignees View on GitHub
android area: cdk/overlay ios P2
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

FlexibleConnectedPositionStrategy seems to incorrectly calculate positions for overlays with `overlayY: bottom` on mobile devices, but only when the address bar is hidden. It doesn't matter if the page is scrolled or how the elementRef is positioned. As soon as the address bar is visible there is no issue.

### Reproduction

StackBlitz link: https://building-tooltip-ovwh6v.stackblitz.io/

Steps to reproduce:
1. Open the example at https://building-tooltip-ovwh6v.stackblitz.io/ in a mobile browser (tried on Pixel 7 and iPhone 13).
2. Scroll down until the address bar is removed, but the button still has enough room on top to display a tooltip.
3. Hover over or click the tooltip button located at the bottom of the page.
4. The tooltip that should appear above the button is displayed in the wrong position.
5. Scrolling to the top moves the tooltip to the correct location.

### Expected Behavior

The tooltip should appear in the correct location, even when the address bar is hidden on a mobile browser.

### Actual Behavior

On mobile browsers, when using a position strategy with `overlayY: 'bottom'` for a tooltip, the tooltip's location becomes incorrect when the address bar is hidden. This seems to be affecting the calculation of the tooltip's position, placing it in the wrong location on the page.

**Position Strategy Used:**
```
{
originX: 'center',
originY: 'top',
overlayX: 'center',
overlayY: 'bottom',
offsetY: -8,
}
```

### Environment

- Angular: 16 (example shows it exists in 7 as well)
- Browser(s): Chrome
- Operating System: iOS/Android

Contributor guide

Open the contributing guide

Research direction

Start with Angular Material's FlexibleConnectedPositionStrategy and reproduce the StackBlitz example on Chrome mobile browsers with the address bar hidden. Compare the calculated tooltip position for overlayY: 'bottom' while scrolling; done means the tooltip remains correctly positioned above the button on the listed mobile environments.

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
38/100

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