You can see something like this on several trade pairs. To be more specific we consider the BTCZ/BTC pair like one of such pairs in the example below.
It means the amount you inputted is multiplying by 10.
This happens because the price of the BTCZ consists of the number of nine places to the right of the decimal point. It means the price for the 1 BTCZ is lower than 0.00000001 BTC.
Take notice, STEX uses numbers of eight places to the right of the decimal point. To make trade possible, the BTCZ amount you input is multiplying by 10.
It means if you input 1 in the amount field, you actually buy/sell 10 BTCZ per the price you choose.