[calmon]

There are a big problem with dispel spells:

First the (possibly) known bug with dispel:
After dispelling a global entchantment there is a free slot in the list but this one is still 'protected' with the additional gems from the former spell.

This bug means you can make a deadlock for globals in endgames:

Maximum gem input for a global entchantment are 999 in sum. This means a low cost entchantment like 'gift of Health' (40 gems) can be strengthened by 959 additinal gems. After a dispel no other spell (except gift of health) can fill this empty slot because there is no way to bring the 959 required additinal gems. Magical sites with bonus helps sometimes, but rarely.