[Rainrider]

It doesn't work. Used the code you provided as follows:

local SortAuras = function(a, b)
	if (not a or not b) then return end

	if(not a:IsShown()) then
		return b.isDebuff
	elseif(not b:IsShown()) then
		return not a.isDebuff
	elseif(a.isDebuff == b.isDebuff) then
		return a.timeLeft > b.timeLeft
	else
		return a:GetID() > b:GetID()
	end
end

and set timeLeft for the gap aura to -5 in PostUpdateGapAura (I noticed timeLeft could be negative (-0.062 the smallest I got and it happened very seldom, probably some OnUpdate lag)). Some screenshots of the results are attached. Auras without borders are buffs.







Edit:
Also got the following after some time.

55x oUF-1.6.4\elements\aura.lua:307: attempt to index field "?" (a nil value) oUF-1.6.4\elements\aura.lua:307: in function <oUF\elements\aura.lua:287> oUF-1.6.4\elements\aura.lua:361: in function "?" oUF-1.6.4\events.lua:69: in function <oUF\events.lua:62> Locals: ...

and

invalid order function for sorting

which is triggered by lua's ltablib.c

Sorry for editing this that often