Dash multi dropdown menu limit

[sblinz]

I had this exact question and came up with a simple workaround here:

Limit number of values in multi-select dropdown without disabling

I have a multi-select dropdown with many options. I want to limit the maximum number of values a user can select to 3 but I don’t want to disable the dropdown at 3 - I want the user to be able to remove values and add new ones once they reach 3. I tried writing a callback with the dropdown values as both Input and Output. I was hoping that I could check if len(dropdown_values) > 3 then I would return dropdown_values[0:3] for the values. But it seems the same component cannot be both an Input an…