Expected result: If you have a toughness value on a stress track, then set it to 0, the new value should be accepted and saved.
Current result: If you have a toughness value set, then try to change it to 0, the new value is ignored and the old value preserved, to be seen on a reload.
Difference: Make the system accept a value of 0.
Ah, you're right. Perhaps more importantly, it breaks completely when you set it negative. The bounds checking is off. Thanks for the report, I'll fix this ASAP.
Expected result: If you have a toughness value on a stress track, then set it to 0, the new value should be accepted and saved. Current result: If you have a toughness value set, then try to change it to 0, the new value is ignored and the old value preserved, to be seen on a reload. Difference: Make the system accept a value of 0.