I'm getting this warning, when compiling in Fontlab:
[WARNING] <Font> feature 'ss01', referenced in aalt feature, either is not defined or had no rules which could be included in the aalt feature.
----
[WARNING] <Font> feature 'ss01', referenced in aalt feature, either is not defined or had no rules which could be included in the aalt feature.
----
feature aalt {
# Access All Alternates
#> feature
feature lnum;
feature ss01;
feature ss02;
feature locl;
feature salt;
feature hist;
feature case;
#< feature
} aalt;
---
feature ss01 { # Stylistic Set 01
sub D E by D_E;
} ss01;
---
What am I doing wrong? Or should this warning just be ignored?