Fees are paid after action done

The chain only deducts fee at the end of operation execution (if not, please open an issue in bitshares-core). That said, if any action that will cause an increase of balance, the user can use part of that to pay transaction fee.

For example,
* when cancelling an order, some funds will be returned which can be used to pay the cancellation fee.

If UI is smart enough, it should detect if there would be a balance increase when the user has no enough balance to pay fee.

Alternatively, UI can just let the user to select an asset to pay fee, but **don't simply prevent user from trying an action just because the user seems to not have enough balance to pay fee**, which is stupid assumption (another stupid thing is described in https://github.com/bitshares/bitshares-ui/issues/1285).

Related issues: #1412, #1450.

Start by reviewing related issues #1412, #1450, and #1285, then trace the UI flow that blocks actions when the apparent balance cannot cover the fee. Done means actions that return funds can proceed when those funds cover the fee, or the user can select another fee asset without being rejected solely for the initial balance.

Written by the indexing model from the issue text.