Foundation-sites: [Reveal] Opening modal create additional scrollbar to body element in Foundation v6.4.4-rc1 (doesn't happen in v6.4.3)

[drionix]

How to reproduce this bug:

1. Create a Reveal component normally (code from docs also applicable)
2. Open the modal

What should happen:

Modal open normally

What happened instead:

Modal open and add 2 scrollbars to the body

Browser(s) and Device(s) tested on:

Chrome Version 63.0.3239.84 and Firefox Version 56.0 (probably all browser)

Foundation Version(s) you are using:

6.4.4-rc1 (the issue doesn't exist on 6.4.3)

Test case link:

https://codepen.io/lukeyouell/pen/VrGvQP

[ncoden]

I cannot reproduce it on Firefox & Chrome on macOS, but I can reproduce it on Windows.
Also, i have an other bug for Firefox on macOS: the gradient background disapear when the modal is open.

[ncoden]

This comes from html.is-reveal-open and .reveal-overlay that both have overflow-y: scroll. So a scrollbar is showed on these two elements even if it is not necessary.

However, I seen there was way more complicated issues on this before, like: https://github.com/zurb/foundation-sites/pull/10583. So if the easy solution would be to replace overflow: scroll by overflow: auto, I don't think this would be the right thing to do.

@isapir Could you give me some help there ?

[ncoden]

For the background bug on Firefox, see https://github.com/zurb/foundation-sites/issues/10791

[isapir]

@ncoden I don't remember the details and have no time to look deep into this, but given the information that you already know, why not simply add:

.reveal-overlay {
  overflow: inherit;
}

See https://codepen.io/isapir/pen/EoWjdb

[ncoden]

I am afraid on the simply word there. The PR you made should have fixed this bug, and I don't understand everything in it. But in the worst case I'll go the the __too obvious__ idea of overflow: auto.

[isapir]

My tests showed that it did fix the issue, but there are too many factors here (e.g. other patches by other developers) and I really do not remember the details.

I will try to look into it at a later time, but can't ATM.

[ncoden]

Don't worry, it can wait. And thank you.

[DanielRuf]

Do we need some more testing here?

[ncoden]

poke @isapir

[ncoden]

See #11065