Looks like I got the meaning of Balance and Equity round the wrong way. Which means the demo account is running at a loss. If that's the case, then...
Why is the graph going up ?
Why does myfxbook say profit of $1035.34 and a Gain of +20.71% ?
Balance:
When you have no open position, balance is the amount of the money you have in your account. For example, when you have a $5000 account and you have no open position, your account balance is $5000.
Equity:
Equity is your account balance plus the floating profit/loss of your open positions:
Equity = Balance + Floating Profit/Loss
When you have no open position, and so no floating profit/loss, then your account equity and balance are the same.
And for example when you have some open positions and they are $1,500 in profit in total, then your account equity is your account balance plus $1,500. If your positions were $1,500 in loss, then your account equity would be your account balance minus $1,500.
Definition taken from:
http://www.forexoma.com/leverage-margin-balance-equity-free-margin-and-margin-level-in-forex-trading/