Multi-Combo Box | SAP Fiori for Web Design Guidelines
How to create multi-select drop down list in Excel
How to create multi select dropdown - Esri Community
GitHub - RWS/Multiselect-ComboBox: The multi selection combo box is a WPF custom control with multiple item selection capabilities, along with customizable features to group, sort and filter items in the collection.
codeigniter - html combo box or select box for multiple selection - Stack Overflow
Multi-Combo Box | SAP Fiori for Web Design Guidelines