Please help! Our checkboxes have turned into a dropdown menu!

Please help us! In our app we have an object with a field for the many side of the connection. As you know you can set the field to display a dropdown menu or checkboxes. Our settings are set to display checkboxes. But now..

Because there are more than 500 connected records the checkboxes have mutated into a dropdown menu.

So eventhough 500 records will never be displayed due to filters it still displays the dropdown menu because of the 500 limit.

The tip was to try and write a javascript solution but we don't know how to do this. And this is the first object to have this problem but the database is growing exponentially so in a few months we will have this problem on a lot of objects. Please help us! We don't know how to solve this.

Thankyou Andrzej for your suggestion! We have the category field already in place I'm affraid. Due to all the filters and everything the dropdown menu or checkboxes only show about 20 records but this doesn't make a difference for the checkboxes mutating into a dropdown menu because of the 500 connected records limit.

It might be a little uncomfortable to have over 500 checkboxes or even 500 entries dropdown menu. The solution for you might be to divide all those entries into some subsets by adding another 'category' field to your object. You can choose 'category' first and 'filtered entries' than. Is this might work for you?