Can not create boolean Calculated Column

I wonder if I either do something wrong, or perhaps it is just not supported.

I am just trying to make this simple Calculated Column in my Calculation View

It doesn't matter if the formula is

if("TotalVltdStockQuantity">0,1,0)

or

if("TotalVltdStockQuantity">0,'true','false')

both is returning this, when I click »Validate Syntax«

But when I click »OK« on the Calculated Column, the window closes, but the Calculated Column is not created - why?