PlantUML salt diagram example

This example is to explain a solution to issue https://github.com/pjkersten/PlantUML/issues/16

<uml>
salt
{
  Just plain text
  [This is my button]
  ()  Unchecked radio
  (X) Checked radio
  []  Unchecked box
  [X] Checked box
  "Enter text here   "
  ^This is a droplist^
}
</uml>

will be rendered as: