Bindable XML children - strange behavior

Question

Hi people, I've run into a strange problem and I'm completely puzzled over it.
I hope someone is able to help me with it.
Here's my situation:
I have an mxml module, which we can call "BaseModule", that contains a [Bindable] protected XML variable, let's call it "selectedBeer" for reference. It is instantiated with null on module creation, but populated with XML if some specific ui feature is clicked. In this XML, there are two child XML nodes relevant to my problem - let's call them Price and AlcoholContent.
Now, I have another module, call it "BeerChoosingModule", that extends "BaseModule". It has, among other things, two spark NumericStepper components. Here's how their mxml looks:
<s:HGroup verticalAlign="middle">
          <s:Label text="Selected blah's X:" />
          <s:NumericStepper snapInterval="0.01" stepSize="20" id="desiredPriceEditor" change="changeSelection(event)" minimum="0" maximum="99999" width="120"
                    valueParseFunction="this.PandACFormatter.parseNumber" valueFormatFunction="this.PandACFormatter.format" maxChars="10"
                    value="{this.selectedBeer== null ? 0 : this.PandACFormatter.parseNumber(this.selectedBeer.Price)}"/>
</s:HGroup>
<s:HGroup verticalAlign="middle">
          <s:Label text="Selected blah's Y:" />
          <s:NumericStepper snapInterval="0.01" stepSize="20" id="desiredAlcoholContentEditor" change="changeSelection(event)" minimum="0" maximum="99999" width="120"
                    valueParseFunction="this.PandACFormatter.parseNumber" valueFormatFunction="this.PandACFormatter.format" maxChars="10"
                    value="{this.selectedBeer== null ? 0 : this.PandACFormatter.parseNumber(this.selectedBeer.AlcoholContent)}"/>
</s:HGroup>
Wherever AlcoholContent and Price get used, they get used together and in exactly the same way (i.e. if they are converted into a string for something, they both are, using exactly the same syntax, etc.)
Now, the inexplicable behaviour seems to occur at the binding. If I try to change the value of the desiredPriceEditor in the UI as the application is running, I am able to change it just fine, and then the changeSelection(event) function works, assigns a new value to selectedBeer.Price manually, and everything's hunkey-dory. However, if I try to change the value for of the desiredAlcoholContentEditor, as soon as the UI tries to apply the change, it gets reverted back to the original this.PandACFormatter.parseNumber(this.selectedBeer.AlcoholContent).
Any ideas on what's going wrong here?

Answer 1

Thanks for the reply.
Yes, it would. However, in the situation I described, the if the XML would change, it would change for both the Price and AlcoholContent nodes at the same time. Nothing like this happens for the Price node. Now, in the changeSelection(event) function what I'm doing is something like:
selectedBeer.Price = desiredPriceEditor.value.toString()
selectedBeer.AlcoholContent = desiredAlcoholContentEditor.value.toString()
Could it be that because I'm changing the Price node first, the binding is triggered for the entire selectedBeer object, so the desiredAlcoholContentEditor.value property gets reset to this.PandACFormatter.parseNumber(this.selectedBeer.AlcoholContent) value before the second line from the code above even gets to execute?