ecart 5 - third day use - new cart columns not in calc dropdown

Wanted to set up individual items to apply VAT to.

Added Taxable column to Cart as number
Added taxable column to DB as int
Added Taxable =1 to add to cart server behaviour

Go to....TAX CALC

I dont get
If item TAXABLE exists
instead of a dropdown there's a text box ????? - see attached
AMEND: OK I can manually enter Taxable - but why do the other options use a dropdown ?


Went to add

Total of [TotalPrice] where [taxable] has a value of [1] [times] [<your tax rate>]
to tax calculation

[Taxable] ISN'T in the calculation dropdowns
AND A column I deleted from ecart (Duration) is still there

see attached

I just can't see sense in what is going on here?

AMEND: Yet another bug?
these columns have been added but are not shown in the calculation dropdowns at the bottom of the tax cal wizard
Also mentioned in this thread
showthread.php?t=4919


Lastly

Do it by hand

function WAEC_eCart1_TaxOnlyItems() {
$totalTax = 0;
if (true && (($this->InCart("Taxable") == false))) {
$totalTax += ($this->ConditionalTotal("TotalPrice", "Taxable", "1") * .175);//Result
}
return WA_eCart_FormatNumber($totalTax, $this->ForceDecimalsC, $this->DecimalPlacesC);
}



why does this function only work if ==false ??
if (true && (($this->InCart("Taxable") == false))) {

rather than
if (true && (($this->InCart("Taxable") == True))) {