i did some research after posting this question, and there is no way to do this now that there is a preview screen. you can mix it for your armor, but you cannot save the bottle of dye when you are done. so therefore this cheat doesnt work anymore.

u could try mixing them than add both to armor

Hello.. I have tryed to mix silver and yellow but how dos it work it won´t mix together do i need a bug to do it !

u have to double click on 1 dye then click on anoth dye to mix them.
ex.yello and blue make green it doesent matter what order u mix them in
well im glad i could help. peace im outta here

first u double click on 1 dye then use on item then put the other dye with that armour ex
using gold and silver on a wepon
put the yellow and the silver on the same weapon and walla u got the mix

click dye then armor pops up dye preview screen throw another dye with current dye,
done...

double click on one then add to another

that doesnt work

im having same problem not just you