[Bug]: Select options do not appear inside Slideover body

[asphum]

Component

Select, Slideover

Describe the bug

Describe the bug

Select inside Slideover {#snippet body()} opens but the item list is empty / not visible.

Repro

<Slideover open portal={false} title="Test">
  {#snippet body()}
    <Select
      bind:value={mode}
      items={[
        { value: "a", label: "A" },
        { value: "b", label: "B" },
      ]}
    />
  {/snippet}
</Slideover>

### Reproduction

Expected
Dropdown shows A / B.

Actual
Trigger opens, no items.

Notes
Select defaults portal={true}, content z-50 — same as Slideover overlay/content.
body wraps ScrollArea (overflow-hidden) so portal={false} clips the list.
sv5ui 2.7.0, bits-ui Select.

### sv5ui version

2.7.0

### Area

Not sure

### Checklist

- [x] I searched existing issues and this is not a duplicate.
- [x] I reproduced this on the latest version of sv5ui.

[ndlabdev]

Thanks for the report. I could confirm it, with one extra condition that the snippet above does not include.

When it happens

The list disappears when a Slideover with portal={false} sits inside an ancestor that creates its own stacking context with a z-index above 50, for example a layout wrapper like this:

<div class="relative z-[60]">
    <Slideover open portal={false} title="Test">
        {#snippet body()}
            <Select bind:value={mode} items={[{ value: 'a', label: 'A' }, { value: 'b', label: 'B' }]} />
        {/snippet}
    </Slideover>
</div>

The Select renders its list at the end of <body> with z-50. The inline Slideover belongs to the z-[60] wrapper, so the whole panel paints above the list. The list is open and correctly positioned, just hidden behind the panel. Without such an ancestor, the snippet in the issue works as expected.

About the two notes in the report:

• The shared z-50 alone is not the problem. It only breaks when the container is trapped in an ancestor above 50.
• The ScrollArea in the body does not clip the list. The list is position: fixed, so overflow: hidden has no effect on it. Setting portal={false} on the Select actually works around the issue.

Workarounds until the fix is released

Either of these works today:

• Pass portal={false} to the Select (and any other floating component) inside the container.
• Let the Slideover use its default portal.

Fix

Modal, Slideover, Drawer and Popover with portal={false} now render nested floating layers in the container's own stacking context, above its panel. This covers Select, SelectMenu, DatePicker, DateRangePicker, DropdownMenu, Popover, Tooltip, ContextMenu, a nested Modal and Lightbox, including a scrollable Modal. Containers that use the default portal are unchanged.

The fix is in #219 and will be part of the next release.

If the list is still hidden after upgrading, please share a runnable reproduction (for example a StackBlitz) and I will take another look.