http://boards.cityofheroes.com/showflat ... ost3750155
There are two classes of Defense - Positional and Type.
Positional Defense - Ranged, Melee, and AoE
Type - Cold, Fire, Smashing, Lethal, and so forth.
Everytime you take damage it has a position and specific type: Ranged Fire, Melee Smashing, and so forth.
So - Powers grant you Defense of a positional kind or of specific type. The description will tell you.
Combat Jumping - Melee and Ranged +Def
Wet Ice - Smashing, Lethal, Fire, Cold, Energy, Negative +Def
Let's say you have both on and take Melee Smashing damage.
The game will see which of your +defs (positional or type) is higher (Melee or Smashing) and use the larger of the two.
Now Weave has a +Def to Melee and Ranged as well. If you have Combat Jumping AND Weave on then they stack because they are the same kind of +Def.
The bottom line is +Defs stack ONLY if they are the same kind.
The new +Def inspirations grant you +Def % to ALL Def classes - all positions and types.
I believe the only new thing here is the new insp.
So if you have lethal and smash DEF, weave/combat jump won't improve your DEF on those attack types. But will improve DEF like SR. It was only in the last patch, where CJ/Weave improved FF shields.