[1.7.0.57 β] Stylistic Sets button doesn't allow to disable Set

[SirPL]

Steps to reproduce:

1. Create a text frame and fill it with any text.
2. Select the text.
3. Go to "Character" panel and enable Stylistic Set using a button in Typography section. (In case of Arial there's Stylistic Set 2 available)
4. Perform step 3. once again in order to disable the Stylistic Set. --> Doesn't work: the Stylistic Set can't be disabled that way.