Corrected entry: During the raid on the Separatist base, Ahsoka ambushes two battle droids and cuts them in two from behind, shown via the shadows cast on a wall. In the process, the blade of Ahsoka's lightsaber is shown casting a shadow - since the blade of a lightsaber is a light source, being made of glowing plasma, this shouldn't be possible. (00:12:45)
skater49th
1st May 2018
Correction: That's not exactly how casting shadows work just because it emits light. Any light source will cast a shadow from a stronger light. It's canonical that lightsabers cast shadows, being that they are more opaque than just a beam of light (such as from a flashlight). If you can't see through the lightsaber, then light can't penetrate it either and it'll cast a shadow.