I dunno if this should be in the bug reports/suggestions area, but...
What if, in Profile Fields Builder, your "Join Form" needs to use Lkey and your "View Profile" needs to use Lkey2?
As it is now, when you change a block's "Used lang. key" it changes it for all instances of that block in the entire Profile Fields Builder...It would be useful if admins were be able to set different Lkey's for different things, like for visitors vs members when viewing profiles for instance...