One of the advanced features of the BitBoxApp is called Coin Control.
Coin Control adds a privacy enhancing capability by allowing you to choose which unspent transaction output (also known as UTXO) you want to use when broadcasting a transaction.
Enable coin control
To enable coin control, go into the BitBoxApp settings and under “Advanced Settings”, tick “Enable coin control”.
Use coin control
1. Open the account you want to spend from and click “Send”.
2. Click “Toggle Coin Control” in the upper-right corner and select the UTXO(s) you want to use as inputs for your transaction.
3. Continue to make a transaction as you'd normally do.
Using the "Send all" checkbox now only relates to the UTXOs that you have selected as your transaction inputs
When Coin Control is enabled, clicking the "Send All" button, solely the UTXO(s) that you have selected will be used as inputs for your transaction. “Send all” now relates to the the sum of the selected UTXO(s) (minus fees), not your whole account balance.
When using Coin Control it is always recommended to label each and all of your transactions, for easier bookkeeping.