[6.x] fix(combobox): handle object values in selectedOptions lookup

[waldemar-p]

The selectedOptions computed property failed to find matching options when modelValue contained full option objects (e.g., {label, value}) instead of primitive values. This caused the #selected-option slot to receive fallback objects with incorrect labels.

Now properly extracts the optionValue from object-type values before performing the lookup, ensuring the full option object is returned to slot templates.

[duncanmcclean]

Thanks for the pull request! 🙌

This only seems to cover the "currently selected options" case though. There's a lot of other places we assume the value is going to be a string, or an array of strings.

For example:

• If you select another option, its value will be added to the array, rather than the option's object.
• When multiple="false", the page doesn't load and you get a bunch of console errors.
• You can't deselect items.

CleanShot.2026-04-08.at.11.22.58.mp4

We're also in the midst of a big rewrite of the Combobox (#13843) to improve performance and the UX. Merging this now would lead to a bunch of merge conflicts.

For these reasons, I'm going to close this PR. We can re-consider once the rewrite has been merged. Thanks for your understanding!

[waldemar-p]

Thanks for the infos and the feedback.
Those are very valid points.

I'll then patiently wait for the rewrite of the Combobox. :)