Issue number: resolves #28963
---------
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## What is the current behavior?
<!-- Please describe the current behavior that you are modifying. -->
In #28861 I fixed an
issue that caused the wrong content inside of a popover to be
scrollable. This CSS should have been applied, but it broke back when
popover was converted to the Shadow DOM. Fixing this issue revealed a
misconfiguration with the select-popover that caused the select-popover
to no longer be scrollable.
## What is the new behavior?
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this PR. -->
- Content inside of `ion-select-popover` can now be scrolled
Note that I am considering this a bug fix instead of a regression. While
scrolling used to work in select-popover, it only worked by chance. The
`.popover-viewport` styles should have always applied to the
select-popover, thus requiring the use of `overflow-y: auto` in
select-popover.
## Does this introduce a breaking change?
- [ ] Yes
- [x] No
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3. Add "BREAKING CHANGE: [...]" to the commit description when merging.
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## Other information
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Dev build: `7.7.1-dev.11706893059.1bef4b38`

Issue number: resolves #29211
---------
<!-- Please do not submit updates to dependencies unless it fixes an
issue. -->
<!-- Please try to limit your pull request to one type (bugfix, feature,
etc). Submit multiple pull requests if needed. -->
## What is the current behavior?
<!-- Please describe the current behavior that you are modifying. -->
In #28861 I fixed a
bug that caused `.popover-viewport` to have `overflow: hidden`. In
reality, this code should have always applied but due to an incorrect
selector it never did.
As it turns out in
#29211, some
developers were relying on the broken behavior to build their
applications. In particular, developers were using `ion-popover` without
an `ion-content`. The linked change made it so that using popovers
without `ion-content` were not scrollable.
After talking with @mapsandapps we think it makes sense to officially
support this behavior. We support using [modals without
`ion-content`](https://ionicframework.com/docs/api/modal#custom-dialogs),
and we could not think of a reason to not support the same use case for
popover.
## What is the new behavior?
<!-- Please describe the behavior or changes that are being added by
this PR. -->
- If the `.popover-viewport` element has a child content then
`.popover-viewport `will not be scrollable.
- If the `.popover-viewport` element does not have a child content then
`.popover-viewport` will be scrollable.
I implemented this behavior using progressive enhancement via `:has`.
The [`:has` pseudo-class](https://caniuse.com/?search=%3Ahas) has
cross-browser support. Ionic v7 supports some versions of browsers that
do not have `:has` support. As a result, we fall back to the existing
behavior in this environment. Developers are able to get this behavior
on older browsers by explicitly setting `overflow: auto` on
`.popover-viewport`.
Fortunately, we will be dropping support for several of the older
browsers versions in Ionic v8, so the need to do the manual opt-in
should be less frequent as time goes on.
## Does this introduce a breaking change?
- [ ] Yes
- [x] No
<!--
  If this introduces a breaking change:
1. Describe the impact and migration path for existing applications
below.
  2. Update the BREAKING.md file with the breaking change.
3. Add "BREAKING CHANGE: [...]" to the commit description when merging.
See
https://github.com/ionic-team/ionic-framework/blob/main/.github/CONTRIBUTING.md#footer
for more information.
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## Other information
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screenshots of how the component looks before and after the change. -->
Dev build: `7.8.2-dev.11711383079.118d48a5`
Testing:
1. Open https://codepen.io/liamdebeasi/pen/JjVJrZQ?editors=1100 (this
has a dev build installed)
2. Click each button to open a popover.
3. Verify that each popover can be scrolled.
I could not find a great way to automate this test, but let me know if
anyone has ideas!