Basically a giant modification of the wrench menu.

(click the image for full size)
The normal menu would be small and simple for quick things. If you want to get more advanced, you just click 'advanced' and you can start editing very complex things.
Notes:
The 'Emitter Gravity' when on would have any emitter affected by gravity.
The 'Item Collison' when on would have items have a collision. Would only be noticeable if item pickup is off.
The 'Shadow Catching' when on would have shadows show up on this brick. Even if it's transparent. Automatically turns off if a brick is transparent, but you can turn it back on if you want.
The 'Shaders' when off would make the brick not shine. Shadows would still apply, but it just wont have that shader shine applied.
The 'Layer' box allows you to change what layer the brick is in. You could make a water brick in the normal layer or a 1x2 brick in the water layer!
The 'Destroy' button destroys the brick without needing a hammer. Useful if you have no hammer or whatever.
Mostly everything else should be easily understood or is described on the image.