MultiSelect: pressing Tab deselects the focused option

[jouni-kantola]

Describe the bug

Pressing Tab on a MultiSelect that has selected items deselects one of them instead of just moving focus. This happens in two situations:

1. Panel open — tabbing out of the open panel deselects the currently focused option.
2. Panel never opened (autoOptionFocus) — simply tabbing past a closed field deselects the first selected option, without the panel ever being opened (note: only on the first tab-through after the component mounts).

Reproduced on vue@3.5.38 and vue@3.4.31 (StackBlitz template), primevue@4.5.5, @primeuix/themes@2.0.3.

Pull Request Link

No response

Reason for not contributing a PR

• Lack of time
• Unsure how to implement the fix/feature
• Difficulty understanding the codebase
• Other

Other Reason

No response

Reproducer

https://stackblitz.com/edit/primevue-4-vite-issue-template-xwgspziq?file=src%2FApp.vue

Environment

OS: MacOS 26.5.1
Browser: Microsoft Edge

Vue version

3.5.38

PrimeVue version

4.5.5

Node version

24.17.0

Browser(s)

Microsoft Edge 149.0.4022.80

Steps to reproduce the behavior

Case 1 — Tab while the panel is open

1. Render a MultiSelect with :showToggleAll="false" and three of five options selected ([1, 2, 3]).
2. Click the field to open the panel (an option becomes focused/highlighted).
3. Press Tab.
4. Selection drops to [1, 2] — the focused option was toggled off.

Case 2 — Tab past the field without opening it (autoOptionFocus)

1. Render a MultiSelect with autoOptionFocus and three of five options selected ([1, 2, 3]).
2. Focus the element before it, press Tab to move focus into the field — do not open it.
3. Press Tab again to move past it.
4. Selection drops to [2, 3] — the first selected option was toggled off, although the panel was never opened.

A runnable reproduction (both cases) is in the attached StackBlitz / App.vue.

Expected behavior

Pressing Tab should only move focus (and close the panel if it is open). It should never add or remove a selected option.