Currently methods like :addlabel or :addcheckbox require one or more arguments to be passed.
I suggest to have default values for those like :addlabel("") and :addcheckbox("", true) because their values can usually be dynamically adjusted using label:text and button:pressed. Whats missing here is a way to get and set a buttons text attribute.

The reason I ask for this is because i created a small tool (https://lucaelin.github.io/ksml/) that generates kos gui code from xml-files. It currently requires a special param: attribute for elements that have required parameters. I'd like to remove those.