Adding 2nd type of Damage to a weapon?

As a DM I tried to add additional fire damage to a players Rapier. I check boxed DAMAGE2, 1D6, and listed it as Fire. It just shows zero for that damage every time. What am I missing?

1. What game are you playing and which character sheet are you using? 2. How are you rolling that attack? Are you clicking on the button in the character sheet or using a macro? 3. Do you have more than one character with the same name? If you can post screenshots of what you're seeing that may be helpful. The character sheet attack section, the output in chat, etc. This is from the D&D 5E by Roll20 Sheet:

1. What game are you playing and which character sheet are you using?  D&D 5E - the standard Roll20 Charactermancer sheet  2. How are you rolling that attack?  ​ By clicking on the weapon in the character sheet.   Are you clicking on the button in the character sheet or using a macro? 3. Do you have more than one character with the same name?  ​ No,   If you can post screenshots of what you're seeing that may be helpful. The character sheet attack section, the output in chat, etc. This is from the D&D 5E by Roll20 Sheet:

it looks like the default 1d6 is in the damage spot, which doesn't fill out the box, so it is just empty. if you add in 1d6 it should work.