Tenacious Magic
(Player's Guide to Faerûn, page 45, DnD 3.5)
[General]
You can use the Shadow Weave to make your spells harder for Weave users to dispel.
Prerequisite
Benefit
Your spells resist dispelling attempts made by Weave users. All creatures employing spells or spell-like abilities are considered Weave users unless they possess the Shadow Weave Magic feat. When a Weave user makes a dispel check to dispel one of your spells (including using dispel magic to counterspell a spell you are casting), the DC is 15 + your caster level. This benefi t does not extend to spells you cast from the schools of evocation or transmutation.