FlashFirebug

FlashFirebug (now Flash Debugger) gives you the ability to debug any AS3 Flash on the web. Inspect the DisplayList, change properties on the fly and see the warnings, errors and traces directly in the extension. Use the inspector to hone in on elements, transform objects on the fly and use the console to run AS3 commands.

Display Tree

FlashFirebug provides a visual representation of the DisplayObjects inside the SWF file as a tree. The tree displays the DisplayList structure, DisplayObjects' names and types. The Display Tree utilizes icons and styles derived from Adobe Flash IDE which are familiar to all Flash developers and designers. 

Debug multiple

Using FlashFirebug tree you can debug multiple SWF files on the same page.

 

The display tree dynamically updates as new elements are added/removed from the SWF.

Live display tree