The idea is to have a Multiple Select Drop-down, which can enable a form visitor to select multiple options for a property by clicking on a dropdown and searching for an option. This would essentially be an altrenative for Multiple Checkbox Field Type, for when there's too many options in the property.
I've recently faced this issue, where I have a Contact Property field with about 250 different options, with the ability to have multiple options associated to the property. I need to insert this Property into one of my forms, and I find that having this property as a Multiple Checkbox means that the form becomes extraordinarily long, and I have to make the user scroll through each and every option to find the ones relevant to them, along with scrolling through all the 250 options to get to the next form field. This makes for an incredibly bad user experience on the form, and I'm bound to have an insane bounce rate due to this. There seems to be no other usable alternative as of now. I'm using a multi-select dropdown in my Jotforms at the moment. As much as I'd love to move all my forms to Hubspot, the lack of this field type makes it quite difficult for me.
PS. I am a long standing HubSpot Solutions Partner that has helped clients with many items just like this. If you are interested in cleaning and standardizing data with AI scoring leads with AI, building advanced workflows, designing and developing websites I can assist.
6 years, no progress? HubSpot, please react:) While there's a native way in all the modern browsers to implement muti-select, HS forms still do not have such an element. Not in the legacy editor, nor in the new editor.
It's great that this missing feature gives job to developers, myself included, but really it's a so obvious thing to have available without developing.