Characters from other languages support?

I am doing a Stroop test and I need to adapt it for my language, Croatian. Thing is that the colour yellow is called "žuta" in the language and we want the participants to be able to press the "ž" key when yellow appears on the screen. It seems not to function. I tested it with also other characters that are not in English, such as č,đ,š and it does not work. Is there a possible workaround or are these characters just not supported by PsyToolkit?

Thank you in advance for your responses!