R – Flex vertical sliding thumbnails

There is no such native feature in Flex. But, there are a couple of options, commercial and not:

http://www.rogue-development.com/objectHandles.html (free) http://www.flashcomguru.com/components/flex_whiteboard/whiteboard_demo/ (payed)

You can do it by hand, if you wish, it's not very hard. I advice you to use Degrafa (http://degrafa.org/) for the actual drawing since it is way easier than native drawing API and it is opensource.

You need to include the WhiteBoard.swc library in your project. If you're using Eclipse/Flex Builder go to project properties -> flex build path -> library path -> add swc. Or moving it to the libs folder should be enough. The sources for the component are not included in that demo as it is not a free component. I didn't see a demo version either, so unless you buy it, you probably won't be able to run those sources locally.