opera portable taking all memory!

I liked the 12.18 of opera portable but it seems to have no memory management.
I thaught from begining that it's a standard and inactive tabs would 'sleep' but nothing!
Opera was swedish, that was great.
Is there a version coming frome a secure country or is the one after the overtake the only one?
Like said 12.18 seems to be the last one before (first?) owner change and the last one I seemed to use.
Thanx for any asistance!
I need at least one or two backup or 'testing' browsers and opera would be the first besides the main one!
Thanx!