Powder only in a front loader...never heard that one. I have a front loader and the detergent dispenser only takes liquid. I dont even use the special liquids for it either, just a smaller amount of the regular stuff. I do however run it on the normal cycle once a month with a 1/2 gallon of vinegar.
I personally hate a front loader but until this one bites the dust I am stuck with it !!! I will go back to a top loader anyday.