How can i remove spell checking underline in custom interface ?

[bogdan]

I would like to know how i could remove the red line under the text in custom interface. The input in the interface field is not "en" or "ru".
I have tried disabeling in windows by setting Spelling to Off without success. Any help is appreciated.

[Oyasumi Punpun]

https://www.w3schools.com/howto/howto_html_spellcheck_disable.asp