Nice to hear it doesn't crash anymore. Even though we still don't know what was causing it, as there was no explicit fix for it.
Btw, it shouldn't be much slower than usual, "nightly" technically is not the correct term for the builds, I just created them in the same way as release binaries. So if the build is noticeable slower, this might be a new problem, I assume, rather in the updated GTK stack than in Geany itself.