flash actionscript: Is this behavior documented? It has left me utterly baffled.

var a = "string";
if(!a)trace("!a:"+a);

Working in the Flash 8 IDE, I get these results:
Publish settings - Flash 6 AS1
Output - "!a:string"

Publish settings - Flash 7 or 8 AS1
Output - ""

So (!var_str) evaluates 'true' in SWF6, but evaluates 'false' in SWF7 and
SWF8? Is this essentially a bug in SWF6 that was fixed in SWF7? Or is there a
problem with the Flash 8 IDE compiling to SWF6? I'll try compiling with my old
copy of Flash 6 when I get a chance.

[quoted text, click to view]

Yes .. and its all documented in the help files (what's new section) in MX
2004
--
Jeckyl