Most blocks can be middle clicked in creative mode, which will give the player a copy of that block if they want to move it around or place more. This is very nice for testing the behavior of certain blocks.
Crystal spawners cannot be middle clicked in creative mode. Attempting to do so has no effect.
After thinking about this some more, it would make my life a bit easier when it comes to testing some things. Additionally it could be useful for modpack makers.
Most blocks can be middle clicked in creative mode, which will give the player a copy of that block if they want to move it around or place more. This is very nice for testing the behavior of certain blocks.
Crystal spawners cannot be middle clicked in creative mode. Attempting to do so has no effect.