Hi Juanito. I investigated some more. What caused the breakage for me is that gtk2.tcz.dep used to include adwaita-icon-theme.tcz. Now it doesn't. Since gtk2.tcz.dep was the only .dep file on my system that included adwaita-icon-theme.tcz, the theme is no longer getting loaded, causing geany and gtk3's file selection dialog to be sad pandas.
It's clear that gtk3 (e.g., file selection dialog) and geany both need adwaita-icon-theme somewhere in their dependency trees. The real question is: What's the best place to put it?
EDIT: My vote is to add it to gtk3.tcz.dep, and to add it back into gtk2.tcz.dep.