1581789 - The eyedropper does not adjust for user scrolling

Status: UNCONFIRMED

(DevTools :: Inspector, defect, P3)

Description

[joseph_evans]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:69.0) Gecko/20100101 Firefox/69.0

Steps to reproduce:

I opened up the developer tools:
(menu icon)->Web Developer->Inspector
Once I did that I clicked the pipette that lets you select a colour from the page.
This works just fine until you scroll the page while the colour picker is still active.

Actual results:

The browser did not adjust the point that the magnifier was "looking at".

Expected results:

The opposite

Comment 1

[Patrick Brosset <:pbro>]

Thanks for filing this.
There are 2 ways to open the eyedropper today:

1. from the WebDeveloper menu
2. from a color-picker tooltip in the inspector

When the eyedropper opens up, we block scrolling in the page to avoid bad performance (the eyedropper needs to take a screenshot of the page to magnify it, and therefore we would have to take new screenshots while scrolling or zooming or anything like this).
So, in theory you should not be able to scroll at all, and therefore should not hit this problem (ideally we should allow scrolling but for now this is a limitation).

In case 1, scrolling is blocked as normal, so I think there is no bug here.
In case 2, scrolling seems to be possible for some reason (on macOS with double-finger scrolling on touchpad at least), but is very janky which is weird.

So, to me, this bug is about blocking scrolling while the eyedropper is opened, even when it got opened from the color-picker.