When I copy and paste, then sometime on my screen sometimes an “Afterimage” remains of a line ore something else that I copy and paste. It will stay on the screen in every other program that is opened. I have not been able to remove this. Only re-starting the computer seems to remove it. I can sent an example of what I mean. 
Hello,
this is well known bug caused by Internet Explorer, because eM Client use some of it’s functions it happens with our software also.
Anyway you need to contact Microsoft support line, we can’t help you with this issue.
regards
Jan
EDIT: or you can update your IE to newest version.
Hello Jan,
Strange, I have had this problem 4 or 5 times since I started using eM client (on 14th of June of 2013).
But, never before I have had this problem.
Anyway thanks for your reply.