Bug
Glyphs does not decompose components in color layers when exporting fonts. This results in unusable fonts full of empty layers.
Suggestion
In edit tabs a color layer has to be selected to view the glyph in color. Glyphs does not remember this unless the glyph is input via cut/paste, and it is not preserved in save files. In the font tab color cannot be disabled. I think the best way to handle this would be a global color on/off button that affects both the edit and font tabs similar to the sidebar.