The sandboxed limitations of Windows 8 Modern UI applications is fairly well known. Unfortunately, this means that it is impossible to write a Modern UI terminal in the way that we would normally. On the other hand, there are really good motivations for getting a terminal in the Modern UI.
I couldn't find any truly Slackware/KDE way of naturally configuring ssh-agent(1) to work easily with my login process. Most of the existing methods use a combination of .xsession files or some other scripting, but all of that sort of takes away from the KDE side of