[AS] code behaving differently in Editor ≠ InD

Hello Scripters,

just started to overhaul some scripts. And, upon starting to work, i stumble over something, that a) never happened is such way or B) was different in CS6 when I coded these.

The problem:

If I start my AS from the OS ScriptEditor, the scriptpart

display dialog "" & class of curObj as string

is working fine, throwing "PDF".

But if I execute the script within InDesign the dialog is throwing

«class PDF »

I just need a push in the right direction, why/when this is happening…

Thanks in advance.