Form measured width does not respect includeInLayout = "false"

Steps to reproduce:
<mx:Form backgroundColor="red">
<mx:FormItem label="Label 1"><mx:TextInput /></mx:FormItem>
<mx:FormItem label="Label 2"><mx:TextInput /></mx:FormItem>
<mx:FormItem label="This is a longer label" includeInLayout="false"><mx:TextInput /></mx:FormItem>
<mx:FormItem label="Label 3"><mx:TextInput /></mx:FormItem>
</mx:Form>

Actual Results:
The form is quite wide, even though the item with the long label has includeInLayout="false"

Expected Results:
Size measurement should ignore items with includeInLayout="false"

Workaround (if any):
You can probably subclass Form to patch the bug and then use this subclass everywhere in place of Form, but I haven't worked out specifically how to do that.