Introduction
The combobox is a dropdown with a typeahead behavior. It allows to select an option from the list or enter a custom value.
The input needs to show a placeholder text. As the combobox is often used for very long lists of items (where it makes sense to refine the list), the placeholder should also indicate the content of the dropdown list (e.g. favorites, often used, top items...).
Styling and states
The combobox uses the same styles and states as the select.
Behavior
On click the dropdown opens a list of several items for the user to choose from and the cursor is placed in the input field.
As soon as users start typing the list is refined. Once an item is selected, the dropdown closes and the input field is updated accordingly.
Combox in use
Loading behavior
If there are a lot of items in the dropdown it often needs some time to load. The loading distractor indicates this action.
Additional features
The combobox can have additional features:
- Categories: Entries can be grouped in categories to organize the entries. The categories are separated with a line and a headline.
- Two-rowed entries: The additional information can help the user identify entries.
- Disabled entries: Sometimes entries are not available, in that case the entry is still shown, but it is disabled and therefore can't be selected. To give the user some information on why the entry is disabled, the reason is displayed in an overlay on hover (or tap on mobile).

Measurements
x: 12px
Category
Use a H2 headline for the category.Second row
font-size: 12px
color: $gray-500
Line
height: 1px
color: $gray-200
Disabled
color: $gray-400