I am trying to get the slovenian locale but i do not know how to call it. webix.i18n.setLocale(“sl-SI”); does not work.
That is the correct way to call the locale, but you have to make sure it is linked to your page first.
By default, Webix comes with 10 pre-applied locales, the rest of the locales have to be included separately. Webix Pro edition includes over 300 locales, meaning almost every language should be covered. As far as I can see, the package does include Slovenian locale. You can download the pack by going to the Client Area → Downloads → Webix Locales Pack at the very bottom. You can get more information on how to activate the locale after downloading it here.