[flexcoders] set height of a Container back to default? (resize to content)

[Ryan]

I have the following quandary:

I have a container which most of the time resizes to what it's
holding. Fine.

But sometimes I need it to be an explicit height- so i set the height-
also fine.

Then I need to set it back to resize to it's content. Problem. Setting
height to null doesn't work. How can i take away the height property
altogether?

thanks!