Please help me to find a setting.
C.A.T. is buying 100 coins and tries then to sell 99.x, rounds it to 99 coins, so I am left with 1 coin dust.
Where is the settings, that it does not take ALL coin?
It might be only on Binance, since the fee is paid here in BNB.
C.A.T. have internal rounding routines that are applied before perform a buy/sell actions.
There are situations where fees must be pre-calculated (ex 100 Qty - 0.XX% of 100 in Fees = 99,XX QTY you can sell)
There are situations where user decide where fees are taken (from the main currency, from the partner currency, from another main currency).
In general CAT is not able to have a fee policy 100% equal to the exchange.
Rounding is always performed on the lower value : Example with max 3 decimal digits 9.9999 -> 9.999
Sometimes dust qty can result, like the case you post.