Checkbox checked then add
In the invoice solutions, there is the tax checkbox. Obviously if checked, it makes the tax amount.
In the portal for items, etc (same place as the tax box) , I want to add a checkbox, that if checked it will total the amount on that line in another field.
Basically I want to put materials and services on the lines. If it is a material, I want to check the box, so I can get a materials total of JUST the materials in another field called materials total.