When I open the trade window with someone, there's an option "You're offering:"
and you currently can offer All or some deck..
When I have more decks I use and from which I don't want trade cards, there's a problem what to choose to be shown. Of course I cannot choose the deck I use, so I have to choose "All" - but there again, those cards I use are shown, and I have to write many times "sorry, can't trade this one, I am using it.."
See the problem? I hope so

Suggestion;
simply put on an option
"You're not offering"
and there more decks possible, or even single cards...

or if anyone comes with anything better, I'll be only glad..
thanks!

You can put all your trade cards into a deck and select that for you're offering, you just have to update it every time you get new cards.

Rufio yes, that's what I am currently doing, but already with few hundred cards it lags - and you know how hard it is to track it, what's in, what's not, what was sold on market, what traded ....
And what those players with thousands of cards would have to do?