It shows only the dirt blocks , as dirt blocks, it shows the hidden tnt blocks only after you hit the dirt block that the hidden tnt is in, but it is too late, because you lose the game. If I config the x-ray to show you everything else except dirt blocks, it shows nothing under the game's dirt blocks, like they are normal dirt blocks...
Ps. The x-ray texture pack dose not work, as well.
I was thinking, isn't it possible to create a emulator, that will "virtually" hit the block and if it shows information, different from the information that the dirt blocks have, to tell you that there is something else then a dirt there?