I asked Shawn the following question and he requested I post an example here for him to look at. Thanks for any assistance.
Question: I am trying to use the validation of field A to also make field B enabled, editable, and if feasible, required. (Previously field B would be non-editable and not enabled) I would like for the validation on field A to trigger whether the user tabs out of the field or presses the enter key after entering a value in field A.

My code - I started with some code that I had done while trying to do the on line "Flex in a week" tutorial, and added some fields as I was testing various things. The two fields that I am using for the issue in the question are the 'fullname' and 'address' fields. I have set the 'address' field to editable="false" enabled="false" and want the successful validation of the 'fullname' field to make the 'address' field enabled/editable for input and navigate to it.

Code:
<?xml version="1.0" encoding="utf-8"?>
<mx:Canvas xmlns:mx="http://www.adobe.com/2006/mxml"
borderStyle="solid" borderColor="#D4D4D4"
dropShadowEnabled="true" dropShadowColor="#B3B3B3"
shadowDirection="right" shadowDistance="10"
creationComplete="init()" height="630" width="696">

<mx:Script>
<![CDATA[
import mx.collections.ArrayCollection;
import mx.controls.Alert;
import mx.events.CollectionEvent;
import mx.events.FlexEvent;
import mx.events.ItemClickEvent;
import mx.events.ValidationResultEvent;
import mx.validators.Validator;
[Bindable] public var selectedOptions:ArrayCollection;
[Bindable] public var formIsValid:Boolean = false;
[Bindable] public var formIsEmpty:Boolean = true;
// Holds a reference to the currently focussed control on the form.
private var focussedFormControl:DisplayObject;

private var myValidators:Array = new Array();
private function init():void{
selectedOptions.addEventListener(CollectionEvent.COLLECTION_CHANGE, addToList);
myValidators = [fullnameV, addressV, cityV, stateV, postalcodeV, phoneV, dateNeededV];
}
private function addToList(event:CollectionEvent):void{
thelist.dataProvider = selectedOptions;
}
private function validateForm():void{
var vals:Array = new Array();
vals = Validator.validateAll(myValidators);
}
//enter="nextField(address)"
private function nextField(formObject:Object):void {
var ti:TextInput = formObject as TextInput;
ti.setFocus();
}
//change="toggleEditControl(address)"
private function toggleEditControl(formObject:Object):void {
var ti:TextInput = formObject as TextInput;
ti.enabled = !ti.enabled;
ti.editable = !ti.editable;
ti.setFocus();
}

// Event handler function to display the selected button in an Alert control.
private function handleCard(event:ItemClickEvent):void {
if (event.currentTarget.selectedValue == "F") {
Alert.show("You selected Female")
}
else {
if (event.currentTarget.selectedValue == "M") {
Alert.show("You selected Male")
}
}
}
]]>
</mx:Script>
<mx:StringValidator id="fullnameV" source="{fullname}" property="text"
valid="{toggleEditControl(address)}" />
<mx:StringValidator id="addressV" source="{address}" property="text" trigger="{button}"/>
<mx:StringValidator id="cityV" source="{city}" property="text" trigger="{button}"/>
<mx:StringValidator id="stateV" source="{state}" property="text" trigger="{button}"/>
<mx:StringValidator id="postalcodeV" source="{postalcode}" property="text" trigger="{button}"/>
<mx:NumberValidator id="numeditV" source="{numericEdit}" property="text" allowNegative="false"
domain="real" required="false" valid="{focusManager.setFocus(memoedit)};"
invalid="Alert.show('Numbers, commas, and a decimal are the only valid characters');" />

<mx:PhoneNumberValidator id="phoneV" source="{phone}" property="text" allowedFormatChars="-"
trigger="{button}" />
<mx:DateValidator id="dateNeededV" source="{dateNeeded}" property="text" allowedFormatChars="/"
trigger="{button}" />

<mx:FormHeading label="Contact Information" x="100" y="4"/>

<mx:FormItem label="Full Name" required="true" x="15" y="27" height="22" width="260"
horizontalAlign="right" indicatorGap="50">
<mx:TextInput id="fullname" />
</mx:FormItem>

<mx:FormItem label="Address:" required="true" x="15" y="51" height="22" width="260"
horizontalAlign="right" indicatorGap="60" >
<mx:TextInput id="address" editable="false" enabled="false" />
</mx:FormItem>

<mx:FormItem label="City:" required="true" x="15" y="75" height="22" width="260"
horizontalAlign="right" indicatorGap="105">
<mx:TextInput id="city"/>
</mx:FormItem>

<mx:FormItem label="State:" required="true" x="15" y="99" height="22" width="260"
horizontalAlign="right" indicatorGap="90">
<mx:TextInput id="state" />
</mx:FormItem>

<mx:FormItem label="Postal Code:" required="true" x="15" y="123" height="22" width="260"
horizontalAlign="right">
<mx:TextInput id="postalcode" height="27"/>
</mx:FormItem>

<mx:FormItem label="Phone:" required="true" x="15" y="147" height="22" width="260"
horizontalAlign="right" indicatorGap="78">
<mx:TextInput id="phone" />
</mx:FormItem>

<mx:FormHeading label="Room Information" x="60" y="173"/>
<mx:FormItem label="Date Needed:" required="true" height="22" width="196" y="196" x="15">
<mx:DateField id="dateNeeded" selectableRange="{{rangeStart : new Date()}}"/>
</mx:FormItem>

<mx:FormHeading label="Selected Options" x="60" y="223"/>
<mx:FormItem label="Selected Options:" y="245" height="209" x="0" width="299">
<mx:List id="thelist"
width="182" height="207"
fontSize="9" borderStyle="none"
backgroundAlpha="0" leading="0" />
</mx:FormItem>

<mx:Button id="button" label="Submit" click="validateForm()" y="459" x="124"/>
<mx:FormItem label="Gender" height="60" horizontalAlign="left" width="129" x="386" y="3">
<mx:RadioButtonGroup id="Gender" labelPlacement="right" itemClick="handleCard(event);" />
<mx:RadioButton groupName="Gender" id="Female" label="Female" value="F" />
<mx:RadioButton groupName="Gender" id="Male" label="Male" value="M" />
</mx:FormItem>

<mx:FormItem label="Memo" x="22" y="494">
<mx:TextArea id="memoedit"
verticalScrollPolicy="auto" x="107" y="399"/>
</mx:FormItem>

<mx:FormItem label="Number Edit" x="299" y="70">
<mx:TextInput x="386" y="99" id="numericEdit" />

</mx:FormItem>
</mx:Canvas>