The button element show a button with a text, icon or text and icon. It can be used to call an action. The format is:

   'type' : 'dropdown',
   'maxwidth' : 30,
   'elements' : ['item1','item2'],

Inherits all settings from guiobject, but have the following unique settings.

'indexchanged' Action to run when value selected changes
'addunknown' Add the value selected if not already in the list if this is set to True
'getfocus' Action to run if getting focus
'losefocus' Action to run if loosing focus
'addempty' Add an empty selection at to to allow to reset back to blank value.
'sort' Sort the list ascending if set to True
'selected' Change selected value to this
'elements' List of elements to show or an action returning a list.

Can be used anywhere a guiobject can be added and inside field with a datamap.