Billing document conditions tab - inactive option

Hi Gurus,

In billing document conditions tab if i select the basic price condition type and click on the details icon the following are displayed -

Condition Class - B

Calculation type - C

Condition category - L

Condition control - A

Condit origin - A

Inactive - X

What does the last option "Inactive" mean?

I have found two invoices. In one it is "Inactive" - X and in the other invoice this option is not displayed at all.

Thanks

Sonalika