Few things i discovered

[luminosis]

1. if you right-click while holding an implacable item, it disappears
2. if tree growth is on, and you place a sapling, then quickly take it back, a tree still grows
3. when broken, sand doesnt drop anything.
4. when you are out of range of a surface and you try to place a block repeatedly, it spams the console with (-1, -1, -1) [HH:MM:SS] map.cpp@661]: invalid y value (getBlock)

[luminosis]

5. you can place candles and saplings in water
6. saplings cant be placed on sand
7. if something is placed in water, you cant remove it
8. if you remove gravel, the above stone will fall as well

ill keep going if you want me to.

[Nredor]

Sure. Continue at will

And btw. Bug number 3 fixed