Kerning window compress function

I have a kerning pair Aogonek @j (the A group is unlocked for this combination). When I run compress in the Kerning window, it deletes this pair and makes a new one: @A @j. Is this a bug? The compress function should only remove unnecessary kerning exceptions, right?

This is what the “compress” command is supposed to do, copying glyph kerning to classes. You need to have a (zero) pair for @A+@j to prevent this.

Ok, I see. Is the zero pair only for Glyphs or does it actually go into the font? I vaguely remember from Fontlab that zero pairs got removed, so when I wanted to have a zero pair exception I had to give it a kerning of 1 or -1.

You only need for the ‘Compress’ function. You could remove it later. And zero class kern values are indeed not exported but that is fine, no need for -1 pairs.