Can't use intended tactic in level 9/10 of Advanced Multiplication World

[ehonda]

Hi, I have encountered an issue in level 9 / 10 in the recently released Advanced Multiplication World.

In the level description, it is specified that the proof should be started by using induction b with d hd generalizing c:

Doing that however results in an error stating we have not unlocked the tactic yet:

I have cleared all levels of all previous worlds (save Power World 10 / 10), and also completed all prior levels of Advanced Multiplication World, so this does seem like a bug, because there aren't any other levels where that tactic could be unlocked.

[abentkamp]

This is already fixed on the dev branch.