The “Trading Enabled / Disabled” switch is located in the top left corner of the application, on the left toolbar.
In the picture above, trading is enabled, meaning that the user can:
Trade
Convert currencies
Transfer money
If trading is disabled, none of the trading functions will be available. However, if trading is enabled, the "Sell" and "Buy" buttons in the Order window will be active.
If trading is disabled and you attempt to perform a Buy or Sell trade, a "Trading Disabled" popup notification will appear in the Order window.