"Multiselect fields () use illegal characters (""{}"") in the NAME and ID attributes. '[' and ']' are not allowed according to the HTML spec. It breaks CSS i.e. the ability for them to be used in CSS selectors e.g. #field3[] is not valid. Please remove the brackets from the ID attribute so we can use CSS/JS on SELECT multiselects. https://www.w3.org/TR/html4/types.html#:~:text=ID%20and%20NAME%20tokens%20must%20begin%20with%20a%20letter%20(%5BA%2DZa%2Dz%5D)%20and%20may%20be%20followed%20by%20any%20number%20of%20letters%2C%20digits%20(%5B0%2D9%5D)%2C%20hyphens%20(%22%2D%22)%2C%20underscores%20(%22 %22)%2C%20colons%20(%22%3A%22)%2C%20and%20periods%20(%22.%22)"