Taxable / non-Taxable in PowerStore

a screen shot showing the problem may be helpful.

When I go into eCart and Create the new Column, it just disappears when I exit the eCart... I am missing something I guess. I add the "Taxable" Column, mark it as integer and then click [OK]. but when I exit eCart and go back in ... it gone. I never get to the server behavior because it does not show up in the eCart (or the server behavior) after I modify the eCart Instance.