Semantic-Org/Semantic-UI · error

You called a dropdown action that was not defined

Error message

You called a dropdown action that was not defined

What it means

determine.selectAction() runs when an item is selected; it matches settings.action against the built-in action map (nothing/activate/select/combo/hide) and against a custom function. If it matches neither (unknown string or wrong value type), it logs this error and the selection does nothing meaningful.

Source

Thrown at src/definitions/modules/dropdown.js:3793

  onLabelRemove : function(value) { return true; },
  onNoResults   : function(searchTerm) { return true; },
  onShow        : function(){},
  onHide        : function(){},

  /* Component */
  name           : 'Dropdown',
  namespace      : 'dropdown',

  message: {
    addResult     : 'Add <b>{term}</b>',
    count         : '{count} selected',
    maxSelections : 'Max {maxCount} selections',
    noResults     : 'No results found.',
    serverError   : 'There was an error contacting the server'
  },

  error : {
    action          : 'You called a dropdown action that was not defined',
    alreadySetup    : 'Once a select has been initialized behaviors must be called on the created ui dropdown',
    labels          : 'Allowing user additions currently requires the use of labels.',
    missingMultiple : '<select> requires multiple property to be set to correctly preserve multiple values',
    method          : 'The method you called is not defined.',
    noAPI           : 'The API module is required to load resources remotely',
    noStorage       : 'Saving remote data requires session storage',
    noTransition    : 'This module requires ui transitions <https://github.com/Semantic-Org/UI-Transition>'
  },

  regExp : {
    escape   : /[-[\]{}()*+?.,\\^$|#\s]/g,
    quote    : /"/g
  },

  metadata : {
    defaultText     : 'defaultText',
    defaultValue    : 'defaultValue',
    placeholderText : 'placeholder',

View on GitHub (pinned to 597843ab84)

Solutions

1. Set action to one of the known keys: 'nothing', 'activate', 'select', 'combo', 'hide', or a function (text,value,element)=>{}
2. Remove the action option to use the default 'activate'

Example fix

// before
$('.ui.dropdown').dropdown({ action: 'activte' });
// after
$('.ui.dropdown').dropdown({ action: 'activate' });
// or a custom function
$('.ui.dropdown').dropdown({ action: function(text, value, el){ /* ... */ } });

var KNOWN_ACTIONS = ['nothing','activate','select','combo','hide'];
function actionIsValid(a) {
  return typeof a === 'function' || KNOWN_ACTIONS.indexOf(a) !== -1;
}
if (actionIsValid(myAction)) {
  $('.ui.dropdown').dropdown({ action: myAction });
} else {
  console.warn('dropdown: invalid action', myAction);
}

function isDropdownAction(a) {
  return typeof a === 'function'
    || a === 'nothing' || a === 'activate'
    || a === 'select'   || a === 'combo' || a === 'hide';
}

When it happens

Trigger: Setting action to an unknown or misspelled string such as {action:'activte'}, or a non-function value like {action:123}. The default valid action is 'activate'.

Common situations: Custom action name not present in the module.action map; typo when copying from docs; passing a value that is neither a known string-key nor a function.

Related errors

• Allowing user additions currently requires the use of labels
• API action used but no url was defined
• No URL specified
• There was an error contacting the server
• Once a select has been initialized behaviors must be called

AI-assisted analysis of Semantic-Org/Semantic-UI@597843ab84 (2026-08-13). Data as JSON: /api/errors/829c7b2be2465342. Report an issue: GitHub.