Whenever I use command blocks in my world, they never seem to work. I checked the settings of the command blocks, and it says they are set to always active below the previous output box, even though the selection box on the left says it needs Redstone. Whenever I set the command blocks to chain or repeating, the text below the previous output box always says impulse. 

Whenever I try to set the offset of a structure block to be below Y coordinate 0, it automatically sets it to be above Y coordinate 0, I think this is because my world is an experimental world with caves and cliffs turned on, but I still think this should be fixed.