After having used the change history for a few days now, I also think it might be better disabled by default so users should enable it explicitly if desired.
@kugel- More importantly, we should document it. At the very least there should be a few lines describing the feature at https://github.com/geany/geany/blob/master/doc/geany.txt?plain=1#L2295.
I will take care of updated screenshots seperately.