Hi, elf!
I'm glad to know, that You've got geany, working as expected and as it must do. No thanks to me, keep them for TinyCore team
Geany is cute, 1.23 version will celebrate 10th birthday this year, still working nice! Excepts Poulsbo, so sad. By the way, in Lubuntu 14.04 geany is 1.23, but don't forget, that it was using the earlier version of gtk. and it worked fine on Poulsbo too. So I think the issue You faced is something that is named regression in gtk. You can obtain geany-1.23 sources from
http://tinycorelinux.net/4.x/x86/tcz/src/geany/ One more note about geany-1.37.1. Size of the package packed for gtk2 was slightly larger, than of packed for gtk3. I think it means, that linking for gtk2 needs additional software layer and it may cause troubles too. In other words for modern geany gtk3 is native while gtk2 is step aside.
In any case if You will make progress in You geany and gtk-s exploration, please share the results.
Have a nice Core!
P.S. 10-year old computers are not equipped with hardware bugs like Intel IME, and one day they can become something, that You can not buy for the money.