open fun <C : FormControl> add(key: String, control: C, required: Boolean = false, validatorMessage: (C) -> String? = null, validator: (C) -> Boolean? = null): FormPanel<K>
Adds a control to the form panel.
key - key identifier of the control
required - determines if the control is required
validatorMessage - optional function returning validation message
validator - optional validation function
Return
current form panel