PROBLEM:
Flashing screen when the nQuery is working on Citrix
SOLUTION:
For versions of Citrix Receiver 4.10.1 and higher, follow the steps outlined here:
https://support.citrix.com/article/CTX230017
Otherwise follow the steps described here:
https://desk.zoho.com/portal/advanceprotechnologies/kb/articles/how-to-resolve-flickering-screen-when-connecting-through-citrix
Otherwise this might be possibly relevant:
http://wpfthoughts.blogspot.com/2015/10/flicker-and-fail-with-clickonce-and.html