If you execute too much fast while merchant window is opened, above macro may sell herbs unintentionally.
If you close all tradable windows or execute macro not so fast, there is no problem.
But if you don't want to take a risk, here is a patch. It closes the merchant window.
Code:
/run CloseMerchant()for b=0,4 do for s=1,36 do i={GetContainerItemInfo(b,s)}c={GetItemInfo(i[7]or 1)}if"Herb"==c[7]and 1==c[3]and 4<i[2]then n="AM"i=GetMacroIndexByName(n)EditMacro(i,n,"","/cast Milling\n/use "..b.." "..s)end;end;end
/click ActionButton12
Make another macro which is unique named "AM" and put it at Main action bar #12, the last box. And execute this macro for milling.