tutorial-1.cljs

(ns lt.tutorial
  (:require [lt.object :as object]
            [lt.objs.tabs :as tabs]
            [lt.objs.statusbar :as statusbar]
            [lt.objs.notifos :as notifos]
            [lt.util.js :as util])
  (:require-macros [lt.macros :refer [behavior defui]]))

(defui work-button [this]
  [:input {:type "submit" :value "Do work"}]
  :click #(object/raise this :clicked %))

(object/object* ::worker
                :name "A hard worker"
                :behaviors [::work-on-click ::on-close-destroy]
                :init (fn [this] (work-button this)))

(behavior ::work-on-click
          :triggers #{:clicked}
          :reaction (fn [this] 
                      (notifos/working "Doing some heavy lifting!")
                      (util/wait 10000 #(statusbar/loader-set 0))))

(behavior ::on-close-destroy
          :triggers #{:close}
          :reaction (fn [this]
                      (when-let [ts (:lt.objs.tabs/tabset @this)]
                        (when (= (count (:objs @ts)) 1)
                          (tabs/rem-tabset ts)))
                      (object/raise this :destroy)))

(let [worker (object/create ::worker)]
  (tabs/add! worker)
  (tabs/active! worker))

This is causing: TypeError: Cannot call method 'call' of undefined

Googling isn't helping and the lightable freenode doesn't seem very active.

I know its not specific to your code, but do you have any idea what it's about?