So, I noticed a shameless bug in Linux causing users to loose their clipboard content when they close an application window that they just copied some text from. I did not think much of it at the time, but tiny bugs, like this one, has a nasty tendency to get on my nerves. I expect basic functionality like this to work. But, this is Linux, so I guess it is just something I will have to live with.
This particular bug has actually been around for over a decade, and it has still not been fixed. I am surprised I did not notice it before. Maybe the reason why I just noticed it, is because I recently switched to KDE. In the past, I have used Unity and Gnome, and I do not remember ever encountering the problem in those environments.
Apparently, the workaround is to install a clipboard manager. I have yet to actually test if it works in KDE, but I will likely update this article once I get around doing that.
In the bug report, it is mentioned that you should install either of: diodon, klipper, glipper, parcellite or xfce4-clipman. Have fun!
Obviously I totally agree that a fix should be included when installing your desktop environment. Users should not have to deal with this silliness.