Just some notes if anyone wants to work on these issues in the future:
* I think with the newer GtkFontChooser, it would be easier to filter out invalid font styles like bold and italic and such, so they aren't confusingly shown to the user. * It would also be possible to add a "None" colour scheme something akin to the one in the Gist linked above, although I expect making it the default would cause more confusion for most users than having syntax highlighting by default. * I'm not really sure what more can be done with respect to using the user's default font as Geany, just like Mousepad and Gedit, already defaults to the "Monospace" font to use the system default font, **without it's bold/italic style** (tested on Xfce).
Related: #608, #1250