Base appearance for drop-down select multiple #12049
Description
What is the issue with the HTML Standard?
Now that we have defined base appearance for drop-down single-select and listbox single and multi select, we should define base appearance for drop-down select multiple.
One thing that makes drop-down select multiple different from other modes is that most implementations have a button to close the picker since choosing an option normally doesn't close the picker. Including and designing such a button is being discussed in OpenUI here: openui/open-ui#1217
Another issue is the fact that MacOS doesn't have a native appearance drop-down multi-select component, but this could be solved by making a drop-down multi-select get rendered only when base appearance is applied (thanks Anne!)