This issue has been around for a while now for me…
Every time I open a file, doesn’t matter if it has been saved the day before or just a minute ago, there seem to be changes, within the file, without me even doing anything… this can be very confusing and creates a lot of uncertainty.
I know the diff tool option, I just find, it’s not a good thing, that things within the font get changed upon opening a file. As long as I don’t change anything myself, the file should close without save dialogue…
When I open a file, some glyphs are marked gray, as the indicator for worked over glyphs is. When I close the file, without having made anything, the save dialogue pops up.
I can not recall, when I had the last version of glyphs, that didn’t have this issue… I’m pretty sure it has something to do with metrics or auto alignment
The 2.3 betas have some nasty problems properly opening stuff that was set up in an older version of Glyphs. For a while it was working, but 874 or 875 broke again.