I saw the error a lot when I had mistakes elsewhere in my code. But it shouldn't really happen. 

> On Mar 18, 2014, at 12:27 PM, stnguyen09 <notifications@github.com> wrote:
> 
> In Source/util/subscribeObservable.js:
> 
> > @@ -0,0 +1,19 @@
> > +define(['knockout'], function(ko) {
> > +    'use strict';
> > +
> > +    /**
> > +     * Returns a subscription to a Knockout observable
> > +     */
> > +    var subscribeObservable = function(container, observableName, action, target, event) {
> > +        try{
> > +            return ko.getObservable(container, observableName).subscribe(function(newValue){
> > +                return action(newValue);
> > +            }, target, event);
> > +        }
> > +        catch(err){
> > +            return null;
> It was actually happening pretty often. When the 'container' doesn't have an observable 'observableName' it just returns null, which you then try to subscribe to and then things choke.
> 
> —
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