MyBB Community Forums

hmm I got problem. Today I created a new category with some new forums at my community. Now I need to move some threads to the new forums... But I can't - the new category and all its forums do not show up in the "Move to" selection box. I checked all permissions, rebuild all caches and cleared all cookies, but the selection box doesn't change.

Any suggestions?

It will do that if you hide the forum from the forum jump.

Try this:
AdminCP -> Forum Management -> Manage Forums -> <edit the forum that won't appear> -> Show in Forum Jump? -> Yes