After playing around with several GUI libraries (GTK+, wxPython, Tkinter) and booting up OpenMPT after some fantastic (or stupid) new idea manifested, took a closer look at the pattern editor and started wondering, "How the hell did they made this work?!". Did some experiments to emulate that, and all of them failed.
Afterwards, i became fascinated by it and started to look at the C++ code. Noticed that i understood about 1/5 at best (might be since i haven't learned template metaprogramming in C++ yet), and not even the part i am curious about.
Developers of OpenMPT, would you be so kind to explain how you managed that feat?
And from what GUI widget is each cell of the pattern even made of? Are they custom or improvised labels, maybe even neither?