Why can't Tobi attack while he is dodging an attack using his Jikūkan Ninjutsu ?
what Tobi actually does is warp away the part of his body that was being attacked to the other dimension.
During the entire anime it is portrayed that Tobi cannot attack while using Jikūkan Ninjutsu because his attacks will pass right through the target.
But while Kakashi was in Tobi's space-time dimension, he managed to punch him, thus indicating that Tobi wasn't intangible.
Is there any explanation or any theory on this matter ?