I can not name entities in Minecraft

I can not name entities in Minecraft.  I have tried to name mobs and animals but nothing shows up. I tried in all three dimensions and I was not able to name any entity. All it shows is the name of the name tag above the hotbar. It gets very stressful when I am making an endermen farm since I can't use an endermite as bait. I would really like to get this bug fixed.