If you have two fonts open in Glyphs Mini (v1.03-21), in my case mplus-1m-light.ttf and mplus-2m-light.ttf (http://mplus-fonts.sourceforge.jp) and replace a glyph from one font with a glyph from the other via copy/paste (in my case, the 2m glyph for U+3054 replacing the one used by 1m) then you’re not able to save the edited font as a .glyphs document. An unspecific error says “Could not save document”.
I don’t know if this is a bug or expected behavior so posting here just in case it’s relevant.
First, thanks for the very quick reply on this and the second item I posted. Re-reading my post now I realize I didn’t fully explain what happened.
In essence - open font A and font B in Glyphs mini. Find glyph in font A, delete it. Find variant of this glyph at same encoding in font B, copy it and paste it into font A. Now, if I leave font B open, I can save my changes in font A. If, however, I first close font B, then try to save my changes in font A, I get the error.
My guess is that the pasted glyph in font A is really just a reference or pointer to its original in font B. If font B can’t be found (because the file is closed) the reference can’t be resolved and font A’s changes can’t be saved.
As I say, this is a guess. I tried to understand what you meant by your reference to file handling since OSX 10.7 but could not follow, you - sorry! In all other instances I could think of, a copy/paste is an independent copy not a dependent link.
Saving the file only works as a .glyphs file. If you opened a TTF, you will need to make a duplicate because the changes cannot be saved in the TTF. Nothing to do with the clipboard.