While this behavior might be useful for single selection comboboxes, it is an unexpected behavior, when you template the combobox items to achieve a multiselection behavior. Is it possible to disable the behavior that the selected item is removed from the available items list?
Set ComboBoxAssist.ShowSelectedItem to true, the selected item is shown.
It appears that the last specification has changed such that the default is to always show all items in the list. https://material.io/components/menus#exposed-dropdown-menu
I think it would be a good idea to change the default to show the selected item. It could be added as a "breaking" change in the 4.0.0 release.
Anecdotally I have already had to make this change is our application, because our users were often confused by not seeing the selected item in the dropdown list.
@jizc I agree, I think changing the default as part of 4.0.0 makes sense.
Most helpful comment
Set
ComboBoxAssist.ShowSelectedItemtotrue, the selected item is shown.