This idea has been merged into another idea. To comment or vote on this idea, please visit MXM-I-34 Allow Saving Invoice with Zero Balance.
I see patients and need to document visits. Sometimes those patients do not purchase anything and will still need to document their pre-paid visit with a zero balance. That is how I keep track of their visits from their package that was purchased. This was a great feature on the MX Merchant 4 that has now been removed. Please bring it back!