dependentObservable doesn't call notifySubscribers on write

https://groups.google.com/d/topic/knockoutjs/bX8ze5S1w8o/discussion

by rniemeyer

HTML

<script src="http://knockoutjs.com/downloads/knockout-2.2.1.js"></script>
<input data-bind="value: valueAsObservable" />

<button data-bind="click: alertMe">What is plainOldValue?</button>

JavaScript

var plainOldValue = "Bob";

var viewModel = {
    valueAsObservable: ko.observable(plainOldValue),
    alertMe: function() {
       alert("plainOldValue = " + plainOldValue);  
    } 
};

viewModel.valueAsObservable.subscribe(function(newValue) {
   plainOldValue = newValue;   
});

ko.applyBindings(viewModel);