I have the problem that the Features popup (window?) is not displayed.
I want to test my Stylistic Sets … Btw. when I export my Font the Stylistic Sets works fine in InDesign. But how do I open the test-window?
I run Glyphs Version 1.4.2 (554) on a Mac with Snow Leopard 10.6.8.
You have to compile features first in Font Info window; at the bottom left of the Features tab, you will find the Compile button. Then you can start testing features in the edit view (Features button is at the bottom left of the window).