I've just run across a really odd behavior, which I'm guessing is a bug. A Canvas container will not let you programmatically set vPosition if the vScrollPolicy is "off".
Is this expected behavior?
Yes. When the vScrollPolicy is "off", you can't scroll vertically.
However, I found that there's an undocumented function called scrollChildren that you can call to scroll the children in the absence of scrollbars:
<mx:Button label="Page Up" click="foo.scrollChildren(0, -100)" /> <mx:Button label="Page Down" click="foo.scrollChildren(0, 100)"/>
Note: Since it's undocumented, it's not supported (and may break your code with future versions of Flex).
If you think vPosition should still do the scrolling even in the absence of scrollbars, you can log a wish:
http://www.macromedia.com/support/email/wishform/
Manish
