1) a s:Group with a width of 100
2) a s:Label inside it with left="10", right="10", textAlign="right"
I would hope that flex calculates the width for the label to be 80 and my text stays right aligned within those bounds with the freedom to grow vertically as I haven't set the Height or maxDisplayedLines properties. But that is not the case!
Inspecting the properties at runtime via flexspy shows that the width has set to an obscene number like 10000 and if I change the text to be really really long, it simply overflows its boundaries from the right side! Which is a bit of a surprise because it goes against my intuition of having textAlign="right", which I had hoped, would at least make the overflow happen towards the left side. Even setting maxDisplayedLines="1" does not truncate the text because it thinks that it can grow up to a width of 10000 before it has to honor that property.
So apparently the right way to do this is to give up on the idea that width will be calculated based on the gap between left and right.
So if instead, for the s:Label, you specify:
a) right="10", textAlign="right" then you'll have text that can overflow towards the left side
b) right="10", textAlign="right" and width="80" then you'll have text that will wrap and grow vertically as it gets longer.
c) right="10", textAlign="right", width="80 and maxDisplayedLines="1" then you'll have text that will wrap and grow towards left until it gets too long and will then get truncated.
I would say that this is really inflexible as I can never have text that grows within its left and right bounds and gets truncated only when it overflows the dynamically calculated width within those bounds... but oh well, such is life.