If anyone gets a chance, please have a look at it.
It'd also be a good idea to do the right thing and delete navigation blocks when their collection is deleted. It's probably an expensive operation though; the collection id is stored in a serialised blob, so perhaps a cron cleanup is the way to go.
Argh, I accidentally pushed this patch straight to refs/heads/master, so it didn't go through gerrit and missed out on being reviewed:
https:/ /gitorious. org/mahara/ mahara/ commit/ e29f0a133e2e7c2 7ccce021d87e3b9 d40d1e5778
If anyone gets a chance, please have a look at it.
It'd also be a good idea to do the right thing and delete navigation blocks when their collection is deleted. It's probably an expensive operation though; the collection id is stored in a serialised blob, so perhaps a cron cleanup is the way to go.