Invalid drag offset when page scrolled after 9.3

[AdrienClairembault]

Subject of the issue

Trying to move widgets while the page is scrolled down lead to unexpected behavior.
It seems there is a noticeable vertical offset between the mouse position and the widget position, which get worse the lower you scroll down the page.
While at the top of the page (no scroll), there is no issue.

Example:

Your environment

Official demo: https://gridstackjs.com/demo/
Latest release is 9.3.0 at this date, which I suppose the demo is using.

Steps to reproduce

• Open https://gridstackjs.com/demo/float.html
• Move or expand the existing widget toward the bottom of the page to expand the available height as much as possible
• Add another widget
• Move the new widget around while the page is not scrolled, which should work as expected without issues
• As soon as you start scrolling down the page, moving the widget around no longer work as expected (there is a noticeable vertical offset between the mouse position and the widget position).

[AdrienClairembault]

Possibly related to changes in b559a6f ?

[adumesny]

@VincentMolinie can you please take a look. yeah scrolled content is something I didn't try before...

[VincentMolinie]

I do reproduce, I will try to check what's going on

[adumesny]

great thank you, as I was going to revert your changes until we have time to fix it otherwise. It's holding other changes I need for work and depend on scroll so can't use 9.3.0 right now

[VincentMolinie]

Okey I think I got the fix, I'll create a PR

[VincentMolinie]

And the fix is here: #2499
@AdrienClairembault can you let me know if it fixes your issue 🙏

[AdrienClairembault]

I confirm that the fix is effective and solve the issue.
Thanks @VincentMolinie

[Jenny3107]

Hello,
For my part, the problem is still present on my website and can be seen on the "Advanced Demo" example. To reproduce, I just set the page height (html tag) to 2000px.

[adumesny]

@Jenny3107 you manually pulled Vincent fix and tried that ? I'm not sure it's the right fix anyway, but away this week so limited access to work on this.

[Jenny3107]

No indeed sorry, I thought it had been put on the "master" branch, I just redid an "npm install" thinking the fix had been added. I tried directly on the site: https://gridstackjs.com/demo/web2.html
No worries, I'll wait, thanks.