Let's start with there should be an Option in the Internet Information Service (IIS) application settings to set the default domain and hide the entry. It's really not that hard, so I don unterstand why Citrix isn't doing it.

Here a short description how to permanantly set your domain and then hide the domain filed from the Citrix Director logon page. 

Citrix Receiver... I don't even no where to start with all the issues I had/have and workarounds I have in place to make Receiver at least somewhat useable. The whole thing with Receiver/StoreFront is so "touchie"...anyway, now I just want to let you know something about proxies with Receiver.

Maybe you noticed, maybe not but scrolling in Office (Excel, Word...) doesn't show the content on Windows server 2012R2 with XenDesktop/XenApp 7.x This can be quite annoying and took some time to find out that Citrix is the reason for it!

Citrix XenDesktop/XenApp 7.x is lacking on some features or functions that was in XenApp for many years. Personally I don't understand why Citrix didn't build them in the product from day one XenDesktop 7 was released. Now Citrix is just creating workarounds on customer requests. What I'm talking about you ask? 

Microsoft in there best moments came up with pining items (shortcuts etc.) to the new Jump List. This is all crap, not just for the reason that Microsoft uses a binary key for the list and the corresponding link needs to be in place, it's also not configurable through group policies!