Rocks'n'Diamonds

I came across this bug in level 8 of 'Bananas Journey' by Eden Corbin (Contributions 2004):
After having hit the nut with the rock, the emerald pops out and falls from the steel wall! I thought that emeralds never could fall from steel walls...

Watch (the end of) this tape: http://www.zomis.net/rnd/download.php?id=405

Emeralds always fall off steel wall!
They also do on the EM engine.

I thought you could turn it off by uncheking "Slip from certain flat walls".

> Emeralds always fall off steel wall!

Only if told to do so in the level editor.

> They also do on the EM engine.

Yep, right -- that's the origin of this (IMHO strange) behaviour.

> I thought you could turn it off by uncheking "Slip from certain flat walls".

Exactly.

After having played RnD for such a long time and not even knowing this...