someone please explain me this power, i f i said i wont do an action with one of my figures... this action stills remain in the pool, and gambit is still stealth

As I see you are new, I will give you a quick tip.

You are going to get your answers more quickly when you post the text of the effect you are questioning.

For example, I'd love to answer your question, but I don't know what Sneak Thief is off of the top of my head, so I need to go get the actual text before I can do that.

(Tip #2....the units section is great, but the text is not always 100% accurate.)

I have Gambit. You are my opponent. The game is 300 points.

On your turn, you have three actions in your pool. This means that you can perform up to three non-free actions.

Gambit can use Stealth until you have used two of those three non-free actions.

ok, but if one of my figs has one action token..., and i decided to not use him, and clean, and use one action... and as i said.. nothing with the action token figure, then can i see gambit??

Your action pool is determined by the game's build total. The number of characters you have on your force...or even the ones available to use...do not factor into it at all.

In a 300 point game you would have 3 actions in your pool. If you have not given 2 or more non-free actions, Gambit can still use Stealth.