Multiselectable Combobox

[JAWS-test]

Many frameworks offer a combobox with input field and multiple selection. All variants I know are not accessible. But the element is often needed. I would be happy if there is a standardization for this element in ARIA APG, which I can use as a reference in the future.

Examples:

• https://experience.sap.com/fiori-design-web/multi-combobox/
• https://www.syncfusion.com/winforms-ui-controls/combobox
• https://select2.org/getting-started/basic-usage
• https://harvesthq.github.io/chosen/#no-results-text-support
• https://multiselect-combo-box-flow.herokuapp.com/
• https://demos.devexpress.com/aspxeditorsdemos/ASPxDropDownEdit/CheckComboBox.aspx
• https://demos.telerik.com/kendo-ui/multiselect/index
• https://demos.telerik.com/aspnet-ajax/combobox/examples/functionality/checkboxes/defaultcs.aspx
• https://www.oracle.com/webfolder/technetwork/jet/jetCookbook.html?component=comboboxMany&demo=multi

In my opinion, the most important questions in this context are

• how is the multiple selection of the element perceptible (maybe we allow aria-multiselectable also for combobox)
• how are the selected elements perceptible when the combo box with tab gets the focus
• how to reach the selected elements with the keyboard and e.g. delete them (in some frameworks they are implemented as buttons after the input field, in others as entries within the combo box)