feat(ComboBox): implement noTypeahead behavior to skip auto-selection during filtering

[layonez]

Thank you for your contribution! 👏

Fixes: #12727

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---

Background

When using ComboBox with the noTypeahead property enabled, items were being automatically selected as the user typed, even though the expected behavior is to only allow explicit user selection. This created confusion as noTypeahead is intended to disable autocomplete/auto-selection behavior, providing only filtering functionality.

Changes

Modified the _selectMatchingItem() method in ComboBox.ts to skip auto-selection during active filtering when noTypeahead=true.

Implementation details:

• Added conditional logic to detect active filtering state:
  • Input is focused
  • User has typed a value
  • No explicit selection has been made yet (!_selectionPerformed)
  • Not navigating with keyboard arrows (!_isKeyNavigation)
• When noTypeahead=true and the above conditions are met, auto-selection is skipped
• Preserved all existing functionality:
  • Explicit selections via clicks still work
  • Enter key with keyboard navigation still works
  • Keyboard arrow navigation still triggers selection (as intended)
  • Default behavior when noTypeahead=false remains unchanged

Testing

Added 5 comprehensive Cypress test cases covering:

• ✅ No auto-selection during filtering when noTypeahead=true
• ✅ Explicit click selection works correctly
• ✅ Keyboard navigation + Enter key selection works
• ✅ Keyboard navigation alone triggers selection (expected behavior)
• ✅ Default behavior validation when noTypeahead=false

[cla-assistant]

All committers have signed the CLA.

[nnaydenow]

Hi @UI5/ui5-team-ctr-ril,

Please take a look

[layonez]

@MapTo0 @ndeshev @StefanDimitrov04 Hi folks, I've seen you recently reviewed/worked on combobox component, could you please take a look at this small bugfix when you'll have some time 🙏

[mavo]

Hello, its been now 2 weeks, without any reaction in this PR whatsoever. This is not really helpful, as we are currently stuck and cannot proceed with our project, hence having bad UX because the component is not usable right now which mades us being stuck with a dropdown that simply shows all options.

What do we need to do in order to get progress here?

I am tagging random ppls that contributed to this repo, as I want to get someone to at least take a look so that this is not just forgotten.
@MapTo0 @ndeshev @StefanDimitrov04 @ilhan007 @vladitasev @pskelin @tsanislavgatev

[hristop]

@mavo as i have written in the issue itself - i have conveyed this to our designers. They have not provided timeline, but they said that this needs to be discussed on their internal round and they will come back to me once they do so. I will get back to you then.

This is something that may be considered backward incompatible, thus we need to be backed up by the design area. We have already checked the code and once we hear from them we can quickly act - either approve or reject the pull request.

The request has not been forgotten, it needs to be discussed and synced in a larger round as there are other technologies that use this components and all design representatives consulted.