Re: [csswg-drafts] [css-forms-1] Should `field-sizing: content` be in base appearance stylesheet? (#11838)

As a web developer working on migrating standard dropdowns to the new customizable select API (`appearance: base-select`), I wanted to share some feedback regarding the default sizing behavior.

With standard selects, the browser automatically sizes the trigger button to match the width of the widest `<option>`, preventing layout shifts when the selection changes. However, when opting into `appearance: base-select`, this legacy behavior is lost, and the select button defaults to a fluid width that fits only the currently selected option.

To prevent layout jank when options of varying lengths are selected, we currently have to choose between:
1. Setting a hardcoded `width` or `min-width` in CSS, which is less responsive to dynamic option content.
2. Implementing complex workarounds, such as using `display: inline-grid` overlay sizer elements (hidden proxies) or ResizeObservers to sync widths.

Having a native CSS mechanism (or UA style default) to preserve the 'size to widest option' behavior for customizable select elements would significantly improve developer experience and layout stability.

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Received on Friday, 17 July 2026 00:48:34 UTC