The mouse kerning plugin in Glyphs 4 does not work properly. It only kerns a row of glyphs, not individual ones
The operation of the mouse kerning plugin is tied to the selection below the edit view, which has changed in Glyphs 4. I need to look into it. Currently, the plugin only works in Spacing mode.
It doesn’t even work in spacing mode on my end.
It only kerns the space glyph in kerning/spacing, kerning and spacing mode. The other glyphs cannot be kerned. I guess I’ll wait for a fix before forking out the $$$