Checkbox from Table not working

Dear Expert,

I’m new to dolibarr. I use dolibarr mainly for ticketing system but now working with most of the module. Recently i’m working with complementary attributes, where checkbox from table is not working properly.

I use this code in value “product:label:255::1”, but only one value showing from this list. but the same code is showing all list if I use Select From Table. Actually I need multiple selection which only available in checkbox.

If you can give me some solution it will be very helpful to me.

Thanks in advance