DE copy/print DRM issue

I added a DRM ePub to my DE library (DE for W7, ver 4.5.126523) that is supposed to be copy- and print-restricted. The copy and print pull-down options in DE are indeed grayed-out but both functions still work via keyboard ctrl-c/x and ctrl-p. The ePub distributor says it's not an issue with the ePub DRM but with the DE app itself.  Thoughts?