Add support for overflow in vertical orientation avatar group #14550

Describe your proposal

The fd-avatar-group component currently supports overflow only in horizontal orientation. When orientation="vertical" is used, the group does not detect container height constraints and never triggers the overflow button — all avatars are always rendered regardless of available vertical space.

Expected behavior

In vertical orientation, the avatar group should:

• Monitor the container height (instead of width) to determine how many avatars fit
• Show the +N overflow button when avatars exceed the available vertical space
• Respect the existing maxVisibleItems input as a hard cap, consistent with horizontal behavior
• Preserve keyboard navigation and accessibility (roving tabindex, aria-posinset/setsize) for the visible subset

Current behavior

The overflow calculation in AvatarGroupHostComponent uses item widths and container width exclusively. In vertical mode, items stack along the block axis, so the width-based logic never hides any items and the overflow button is never shown.

Acceptance criteria

• Vertical individual-type avatar group clips to available container height and shows the overflow button with hidden count
• maxVisibleItems still works as a hard cap in vertical orientation
• Overflow popover opens and shows the hidden avatars (same as horizontal)
• Keyboard navigation works correctly for visible avatars and the overflow button
• No regression in horizontal orientation or group type

Notes

The resize observer hook (fdkResizeObserver) is already applied to the host. The main change is in AvatarGroupHostComponent._calculateVisibility — it needs to branch on orientation and use item heights + container height when orientation="vertical".

Proposed Alternatives

No response

Organization

No response

StackBlitz example(s)

No response

Priority

None

Declaration

• I'm not disclosing any internal or sensitive information.