Thanks for your answers.
CubeTheThird: it's the most naΓ―ve way to power pistons, the problem is that it powers both top and bottom pistons, i use a "proxy" stone block to power only one piston.
Tails: It works only if we works we 2 pistons, in my case it's not possible because i have a big vertical stack of pistons and i need to control each separatly. π
I believe it's a bug because it works separatly, but when the top one is activated, if you activate the bottom one he's stuck in this position, you can barrely remove everything else except the bottom piston, he will keep being stuck. π
I tested in 1.8.
There's no such ghost behavior now. But it's still impossible to activate separately pistons stacked vertically.
And honestly it is a reason I stopped minecraft: you create an object called piston, opening a new world of possibilities. In fact no the possibilities are really limited and the fixes on this was more like "featuring the bug more than fixing it", this is dirty work.
You truly can't do everything you want, there isn't even a simple featured way to extend the size of the pistons, there isn't even the feature of catapulting sand and player when turned to the top. Pistons are a shame, if I wonder what was in the head of the devs when they implemented the piston mod i think about this "meh you want it, get it, happy now?".
This is sad.