I'm not used to programming on Linux, and I guess most Linux developers aren't either. How can I say such a thing? Well you take a look at the core Linux APIs and they are a bit like a 300 page manual on how to make toast.
Most Linux devs tell you "don't use X11, use something like SDL". X11 is the core windowing system for Linux and compared to Microsoft Windows it sucks. And it's not like MS Windows is that fantastic itself, but my god, it is no surprise no one recommends you to touch something like X11. Take a look over the SDL source and how it interacts with X11 and you'll see most of it spattered with comments describing the madness. As to why I'm not using something like SDL to save myself this headache, using SDL limits the effectiveness of the multicore design of RetroCopy.
But oh well, after wrangling with X11 for 8 hours or so I have it working, I believe. It works for me anyhow and one tester that has Linux. There were some small issues I had with lowercasing all the filenames internally that I had to fix for Linux as it is case sensitive. The Linux build should be out tomorrow.