If you are looking for the decompiler itself, visit https://github.com/jindrapetrik/jpexs-decompiler
+ update 2020: WARNING - support of the decompiler is now VERY LIMITED. There are no active developers. This means we will NOT develop new features and/or fix most of bugs. We left the tracker running in case somebody from community would like to work on it. Sorry for the inconvenience.
List of issues#149 AS3 decompilation issue: empty if branches
Author: 
focus
focusDate created:
Type: bug
Visibility: Everybody
Assigned to:
Labels: AS3Obfuscated
State: closed 
Hey, please take a look at the attached file.
I see some weird if() branches there like this:
if(!(ls[_loc2_].n))
{
}
else
{
....
I guess it would be much better to show it as
if(ls[_loc2_].n)
{
....
}
http://i.imgur.com/IOXFwpc.png
as3simple _SecureOpt.swf (2 KiB)
State: new→opened
version 1.6.3u2
This was improved, try it.
State: opened→upgraded
Wow, that was fast! Looks much better now, thank you!
State: upgraded→closed