I suggest you make an entirely new wallet for trading on each exchange that utilizes smart contract. Transfer what you want to trade from your wallet that contains the crypto in question and send it to the new wallet you just created for use on the exchange. That way you only share the privatekey on your new wallet which you have made and dedicated to the use of etherdelta exchange. I do this and I feel much safer.

I suggest you never ever connect your main wallet to anything. Always send to another wallet first then to the exchange. This ensures that you never connect (not even by accident) your wallet to anything else.