Panel, allowScrollOnElement on mobile issue.

[laiprorus]

Environment Information

• Package version(s): "office-ui-fabric-react": "^6.210.2"
• Browser and OS versions: Safari on IPhone

Please provide a reproduction of the bug in a codepen

https://codepen.io/laiprorus/full/pooWjZw

Actual behavior:

The Panel and Overlay components use allowScrollOnElement function from https://github.com/OfficeDev/office-ui-fabric-react/blob/09d5abf9a89b1f2ae31de5427e24279537eb9a4c/packages/utilities/src/scroll.ts.
This function creates touchmove events that prevent the user from paning or zooming document body.
In my codepen, if you use a page on mobile, and use touch pinch to zoom in for example on the button, and then click, panel will open. But since you are zoomed in, you will only see part of it. And since "touchmove" events are prevented, you cant scroll to panels content.
There is no way for my code, that uses Panel component to disable those blocking events and it is also impossible to ensure the user is fully zoomed out before panel opens. And even if user is zoomed out, default behaviour on mobile for elements such as text input field, is to zoom in on that input field, and then the user has hard time to zoom out back.
Im not sure if its a bug or missing feature, but it is pretty breaking behavior for my current project. My workaround was to render this component inside Panel content to enable zoom and paning. const EnableScrollFix: React.FunctionComponent<{}> = () => { React.useEffect(() => { Fabric.enableBodyScroll(); $("div[data-is-scrollable]").each((index, element) => { const contents = $(element).contents(); $(element).replaceWith($("<div></div>").append(contents)); }); return () => { }; }, []); return (null); };
this components is empty, and is just used to get to that "componentDidMount" callback of Panel content. It replaces div that blocks events, with empty div, since i couldnt remove event otherwise. But its very cheesy solution, and especially risky since i am modifying dom elements created by react, with out its knowledge.

Expected behavior:

After Panel opens, user should be able to pan and zoom on mobile devices.

Priorities and help requested:

Are you willing to submit a PR to fix? No

Requested priority:
Blocking

Products/sites affected: corporate internal web application.

[maxwellred]

Thank you @laiprorus! I'll look into this shortly and get back to you.

[laiprorus]

here screenshots of reproduced behavior
https://imgur.com/gallery/emLLZgi

1. zoomed out
2. zoomed in
   3-4 red is area that has scrolled blocked, cant scroll vertically or horizontally with finger in this are. green area sometimes work, since textfield component (or input element that is used by it) allows touch events, but fabric code throws errors in console that it cant use e.preventDefault() on this one.

and another one.
https://imgur.com/gallery/8CkDwsN
in this one user is almost stuck and cannot scroll anywhere.

[laiprorus]

i looked more into the issue. Panel applies allowScrollOnElement to its content. And Overlay, that is created by Panel component, calls Fabric.disableBodyScroll after being mounted. Both of these then create events that then block touch scrolling/paning/zooming on mobile devices.
My workaround from original post caused other issues, so i am now looking for something else. I will try to modify fabric javascript directly, and if i find a solution i will post it and maybe create PR.

[maxwellred]

Thank you @laiprorus! I'm still investigating this and other filed issues so PRs are always welcome!

[laiprorus]

Here is my pull request that allows a workaround for this issue.
#11339

[maxwellred]

@laiprorus Great job and thank you very much for the PR! It looks like there's some merge conflicts preventing the ci/cd checks from running so it'd be great if you could take a look at those when possible, thanks!

[laiprorus]

@maxwellred I resolved the conflict using webtool of github. So i guess now we should just wait for approval or feedback? Or is there anything i could do now?

[maxwellred]

@laiprorus Thanks! I'll reach out to the code owners and see if I can get eyes on.

[msft-github-bot]

🎉This issue was addressed in #11339, which has now been successfully released as @uifabric/utilities@v7.8.0.:tada:

Handy links:

• Release Notes
• Official NPM Release

[msft-github-bot]

🎉This issue was addressed in #11339, which has now been successfully released as office-ui-fabric-react@v7.76.0.:tada:

Handy links:

• Release Notes
• Official NPM Release
• Test the release with Developer Demo Site