Tax Calculation wrong with Attributes

[ron54]

using the latest OSC Max 1.7 i found out that when creating any option for example a checkbox and give that an additional pay, any tax will be STILL added to that item, even when set to "show prices with tax", so I end up with the total price(including the tax) + additional Item(+tax)

I checked the Original OSC 2.2 MS2 and there is the calculation correct. So it must has to fo with the built in "option type feature" (wich i badly need but us now unusable as it produces wrong prices)

Remark: i didnt change any code. whats wrong here?
Ron

[makemethis]

Try setting show prices with tax to false...will display item without tax added in
Also...check how you set up tax classes